Actinomycosis (Worldwide): Actinomycosis is an anaerobic gram positive bacterial infection that features abscesses, fever, and usually follows trauma. Primarily affects cervicofacial area; and also respiratory system/thorax and/or gastrointestinal system (ileocecal region). Treatment is with penicillin, tetracycline, or erythromycin.
Amebiasis: See full discussion (Worldwide): Amebiasis is an amebic gastrointestinal infection (sometimes affecting other systems) that may be asymptomatic, chronic, or acute. Symptoms may include abdominal pain, diarrhea (with blood), weight loss, dehydration. Systemic dissemination is usually to the liver, but may also involve the brain, heart (pericarditis), lungs, and genitalia. Invasive amebiasis is treated with metronidazole and colonization without symptoms is treated with paromomycin or iodoquinol.
Angiostrongyliasis: See Parastrongyliasis below.
Anisakiasis (Mexico, Central and South America, Japan): Anisakiasis is a nematode (roundworm) infection of the stomach or intestinal wall with Anisakis. Manifestions vary according to primary site of infection and improvement usually occurs within a few weeks. Acute gastric anisakiasis has an acute onset of progressive epigastric pain, nausea, and vomiting within hours of ingesting lavae. Acute intestinal manifests as low-grade fever, colicky lower (or diffuse) abdominal pain, nausea, vomiting, and diarrhea. Chronic anisakiasis produces chronic symptoms similar to gastritis, peptic ulcer disease, inflammatory bowel disease, and other GI disorders. Treatment is symptomatic, and in a few cases, surgical.
Anthrax (Any temperate or tropical rural area where animal husbandry is common): Anthrax is a gram positive spore-forming aerobic rod (Bacillus anthracis) cutaneous or pulmonary infection. Cutaneous anthrax is characterized by a dark centered erythematous papule surrounded by edematous and vesicular tissue. The papule enlarges, ulcerates, forms eschar, which later sloughs. Lymphadenopathy, fever, malaise, headache, and nausea and vomiting may also occur. After the eschar sloughs, hematogenous spread and sepsis may occur, with resulting shock, collapse, and hemorrhagic meningitis. Pulmonary anthrax (a concern with respect to biological warfare) is characterized by fever, malaise, headache, respiratory congestion, and pneumonia or mediastinitis. Anthrax is treated with penicillin G or tetracycline. Mortality is high, especially in pulmonary anthrax.
Arbovirus encephalitis (Worldwide - according to specific disease): The most important (highest case- fatality rates) arbovirus or arthropod-borne encephalitides are (1) Japanese encephalitis (JE), which is found throughout Asia and the Pacific; (2) Murray Valley (MV), which is found in Australia and New Guinea; and (3) eastern equine encephalomyelitis (EEE), which is found in the Americas and Caribbean. Severe infections are usually characterized by acute onset of fever, meningeal signs (headache, stiff neck, irritability, nausea and vomiting, delirium, >vital signs), tremors, convulsions, and stupor progressing to coma. Treatment is primarily supportive.
Ascariasis: See full discussion (Worldwide): Ascariasis is a nematode or roundworm infection with Ascaris lumbricoides causing transient respiratory symptoms initially and chronic gastrointestinal symptoms. The adult worms are more than 20 cm. in length, hence are easily seen in stool and may also emerge from the nose or mouth as a result of coughing or vomiting. Treatment is with albendazole single dose of 400 mg po (not FDA approved) or mebendazole or pyrantel pamoate.
Babesiosis (Europe, U.S., Mexico): Babesiosis is a rare tick-borne protozoal infection (Babesia sp.) of red blood cells. Babesiosis is self-limited with a duration of weeks to months and is characterized by irregular fever, chills, diaphoresis, headache, myalgia, and fatigue. Moderate hemolytic anemia, jaundice, hemoglobinuria, and hepatosplenomegaly are common; but the illness is fulminent in some cases, leading to death. Treatment is with clindamycin and quinine OR atovaquone and azithromycin.
Bacillus cereus (Worldwide): Bacillus cereus is a pathogen causing self-limited food poisoning with vomiting or diarrhea and abdominal cramps.
Bartonellosis (Oroya fever) (South America/Andes Mountains): Bartonellosis is a gram negative bacterial systemic infection with Bartonella bacilliformis, which is transmitted by sandflies. Infection is characterized by insidious onset of fever, malaise, headache, myalgia; or in other cases, acute onset high fever, chills, drenching sweats, lymphadenopathy, hemolytic anemia, liver involvement and altered consciousness. Essential features are fever, progressive hemolytic anemia, generalized lymphadenopathy, and exposure to sandflies. Salmonellosis is a common complication of bartonellosis. Nodular (and often ulcerated) lesions occur one to three months after the onset of illness. Treatment is with penicillin, tetracycline, streptomycin, or chloramphenicol.
Bilharziasis or Bilharzia: See schistosomiasis (summary or full discussion).
Blastomycosis (Limited areas of south central and midwestern U.S. and Canada, Africa, Mexico ): Blastomycosis is a mycotic (Blastomyces dermatitidis) infection of lungs, skin, bones, or genitourinary system. The infection may be asymptomatic or may present with cough, fever, dyspnea, and chest pain that may resolve or progress to hemoptysis, fever, lymphadenopathy, weight loss, and collapse. Rough, warty skin lesions occur, as does destruction of bone (ribs and vertebrae) and GU problems among males. Blastomycosis must be differentiated from chromomycosis (see below). Treatment is with itraconazole or amphoteracin B. Also see paracoccidioidomycosis (South American Blastomycosis).
Botulism (Worldwide): Botulism is a severe food poisoning resulting from ingesting the neurotoxin produced by Clostridium botulinum in canned or preserved foods (such as those produced under unsanitary conditions and imported). Symptoms include abdominal pain, vomiting, and CNS disturbances.
Boutonneuse fever (African tick fever, Marseilles fever, tick typhus) (North Africa, temperate areas of Southern and Eastern Europe, Middle East): Boutonneuse fever is a rickettsial (Rickettsia conorii) tick-born fever characterized by an ulcer with a black center at the site of the tick bite. Fever and general maculopapular rash may follow. The disease is usually mild. Treatment is with tetracycline, chloramphenicol, or ciprofloxacin.
Brucellosis or undulant fever: See full discussion (Worldwide, especially Africa, Asia, and the Middle East). Brucellosis is caused by gram negative coccobacilli (Brucella abortus and other B. biovars) transmitted through contaminated milk, animal products, and related. Fever, chills, sweats, aches, fatigue, and joint pain are the most common manifestations. The most commonly affected systems (with a variety of manifestations) are cardiac, respiratory, gastrointestinal, genitourinary, and central nervous system. Long-term treatment 3-8 or more weeks) with medication combination is necessary. Doxycycline + rifampin or TMP/SMX DS tablets + rifampin are commonly used.
Buruli ulcer (Africa, Australia): Mycobacterial (ulcerans) infection resulting in a large ulcer. Surgery may be necessary.
Campylobacter enteritis (Worldwide): Campylobacter enteritis is caused by gram negative non-spore forming rods (Campylobacter sp.) resulting in acute gastroenteritis characterized by fever, abdominal pain, and acute watery diarrhea. Campylobacter fetus causes systemic infections that are sometimes fatal.
Cancrum oris: Cancrum oris is a progressive necrotic ulceration of the face caused by infection with Treponema vincenti and/or Bacillus fusiformis. The infection is found most often in malnourished children and is often co-exists with other infections such as visceral leishmaniasis. Treatment is with systemic penicillin.
Capillariasis, intestinal (Southeast Asia, especially Thailand and the Philippines): Capillariasis is a nematode (Capillaria philippinensis) infection resulting from ingestion of infected raw fish. Onset is insidious with abdominal pain and watery diarrhea. Progressive autoinfection may lead to enteropathy, protein loss, and severe malabsorption. Treatment is with mebendazole 200 mg bid po for 20 days or albendazole.
Cestode infections: See tapeworm.
Chagas' Disease or American trypanosomiais: See full discussion (Most of Latin America): Chagas' disease is a protozoan infection with Trypanosoma cruzi transmitted by insect bite. Patients may be asymptomatic or have a lesion at the site of the bite; and symptoms of prolonged fever, tachycardia, fatigue, weakness, splenomegaly, and lymphadenopathy. Myocarditis or meningoencephalitis may also occur. Most patients experience spontaneous remission of symptoms, followed by a lifelong low-grade parasitemia. There is not currently a satisfactory treatment for any stage of Chagas' disease. Current treatment includes nifurtimox 8-10 mg/kg/day po qid for 90-120 days or benznidazole 5 mg/kg/day po for 60 days. These long-term therapies are toxic to some patients. In the United States, nifurtimox is available only from the Centers for Disease Control and benznidazole is not available in the U.S.
Chikungunya (Topical areas, especially urban, of Asia, India, and East Africa): Chikungunya is an arboviral infection transmitted by the Aedes aegypti mosquito. Incubation is 2-4 days and the illness is self-limiting with acute symptoms (abrupt onset fever, headache, arthralgias, nausea, vomiting, abdominal pain, sore throat, lymphadenopathy, rash at defervescence, and malaise) lasting 3-10 days. Arthralgias remain a problem for weeks to several months after the acute phase. Febrile convulsions may occur in young children. Treatment is supportive for fever and pain.
Cholera (Southeast Asia, India, Middle East, East and North Africa): Cholera is an endemic and epidemic acute Vibrio cholera (bacterial) infection transmitted via feces or vomitus-contaminated water. Raw or under-cooked seafood may also be contaminated and result in cholera infection. The incubation period is 1-5 days. Most infections are subclinical, but 10% or fewer infected persons experience sudden and explosive diarrhea (first fecal, then watery and mucous-flecked), vomiting, and prostration leading rapidly to fluid and electrolyte depletion, metabolic acidosis, shock, renal failure, and death. Rehydration (Ringer's lactate initially for severe cases, then oral rehydration therapy; or in milder cases, oral rehydration therapy throughout) is critical. After vomiting ends, the duration of symptoms is shortened by tetracycline 500 mg po qid for 3 days or furazolidone 400 mg daily for 3 days or a single dose of 300 mg doxycycline.
Chromomycosis (Worldwide; greatest in Costa Rica and Madagascar): Chromomycosis is a chronic mycosis of the skin and subcutaneous tissue most common among people (primarily adults) who walk barefoot or are exposed to thorn or similar wounds. The disease begins with a warty papule or pustule, plaque, or ulcer. The lesion progresses to a verrucoid (warty) plaque that thickens with time. Lesions tend to spread by inoculation rather than growing peripherally. Chromomycosis must be differentiated from blastomycosis. Superinfection leads to cutaneous and other complications.
Chyluria (or galacturia): Chyluria is chyle (lymph and triglyceride in an emulsion) in the urine caused by obstruction between intestinal lymphatics and thoracic duct leading to rupture of renal lymphatics into renal tubules. See filariasis.
Clonorchiasis: See trematodes below.
Clostridium botulinum and C. perfringens (Worldwide): C. botulinum causes botulism (see above) and C. perfringens causes gas gangrene and also enteritis or food poisoning especially from poultry.
Coccidioidomycosis (United States, Mexico, and parts of Central and South America): Coccidioidomycosis is a fungal infection with Coccidioides immitis, usually pulmonary (cough, fever, chest pain, weight loss, malaise), but also of CNS, skin, lymph system, or liver. C. immitis occurs naturally in some soils (semi-arid with short rainy season) and is inhaled. Immunocompromised persons are at increased risk. Treatment is with amphotericin B or fluconazole or itraconazole. Maintenance therapy utilizes the same medications, especially fluconazole or itraconazole.
Crimean-Congo hemorrhagic fever: See hemorrhagic fevers (HFs) below or full discussion of HFs (Africa, Middle East, Eastern Europe, Russia, Western China): Incubation is 3-12 days. Crimean-Congo HF is transmitted by the bite or crushing of infected ticks, or by contact with live or dead infected mammals. The clinical picture includes sudden onset fever and myalgia, headache, dizziness, photophobia, hyperesthesias, chest and/or abdominal pain, nausea and vomiting, conjunctival injection, flushing, hypotension, axillary or other petechiae, decreased blood pressure, increased heart rate, periorbital edema, proteinuria, and significant liver abnormalities (>AST, >phosphokinase, >bilirubin), leukocytosis, and signs of disseminated intravascular coagulation. Though treatment is not definitive, more severe cases are often successfully treated with IV ribavirin as described in the full discussion of Hemorrhagic Fevers.
Cryptococcosis (U.S., Australia, tropical Asia, Africa, South America): Cryptococcosis is a yeast (Cryptococcus neoformans) infection beginning in the lungs and spreading to the CNS and thus resulting in meningitis and in some cases, disseminated disease. Immunocompromised persons are at increased risk. Treatment is with amphotericin B alone or in combination with flucytosine. Mild cases may be treated with fluconazole; and fluconazole is also used for maintenance therapy.
Cryptosporidiosis (Worldwide, with increased prevalence in tropical areas): Cryptosporidiosis is a protozoan (Cryptosporidium sp.) infection of the GI tract causing diarrhea which ranges from self-limited to chronic secretory, high volume and ultimately fatal. Immunocompromised persons are at increased risk. There is not currently a satisfactory treatment.
Cutaneous larva migrans (Worldwide, including Southeastern U.S.): Cutaneous larva migrans is a distinctive serpinginous dermatitis caused by hookworm larval penetration of the skin. See hookworm.
Cutaneous leishmaniasis (sometimes termed tropical ulcer or tropical sore): See full discussion of leishmaniasis (East and North Africa, Middle East, Southern Europe, Central, South, and East Asia, South America, West Mexico): Cutaneous leishmaniasis is caused by Leishmania sp. and is characterized by single or multiple lesions typically progress from papules to nodules to non-ulcerated dry plaques or ulcers that usually are painless unless secondarily infected. Lesions are sometimes described as wet or dry. Distribution may be a single primary lesion, multiple primary lesions, and/or satellite lesions. Low-grade fever, regional lymphadenopathy and/or lymphangitis, and lesion pruritis or pain may be present. In many cases, healing is spontaneous within months or years of onset. In other cases, however, the disease is progressive with visceral manifestations or spreading skin lesions. Treatment depends on whether the patient is immunocompromised and/or at risk for mucosal leishmaniasis (in which case, treatment is provided) and on site and severity of lesions, with metastatic lesions treated and inobtrusive lesions not always treated. Treatment includes intramuscular or intravenous antimony preparations such as sodium stibogluconate. Other treatments are pentamidine, miltefosine, or rifampin and isoniazid in combination. Also see full discussion of leishmaniasis or mucocutaneous leishmaniasis.
Cyprus fever: See Brucellosis.
Cysticercosis: See tapeworm.
Dengue Fever: See full discussion (East and West Africa, Southeast and East Asia, Pacific Islands, Eastern Australia, Central and South America, Mexico, South Texas, Caribbean Islands - with distribution increasing, especially in urban areas): Dengue Fever is a flavivirus (several serotypes) infection transmitted by mosquitos. There is increasing incidence and prevalence of cocirculation of multiple serotypes. Dengue is usually a self-limited illness characterized by abrupt onset high (biphasic) fever, chills, headache, rash, signs of bleeding, changes in taste, sore throat, nausea, vomiting, diarrhea, anorexia, severe aching myalgia and arthralgia (hence "bone-break" fever), and depression. Complications include meningoencephalitis, dengue hemorrhagic fever (DHF), and dengue shock syndrom (DSS). Treatment is supportive and convalescence tends to be lengthy.
Diphtheria (Worldwide): Diphtheria is an acute upper respiratory infection caused by virulent strains of the toxin-producing gram positive bacillus, Cornybacterium diphtheriae. Symptoms include fever, serosanguinous nasal discharge, sore throat, and gray pseudomembrane in the pharynx, nasopharynx, and/or trachea. Complications include respiratory tract obstruction, pneumonia, peripheral neuritis, and/or myocarditis. Immunization is essentially universal among younger people in the U.S., but some refugees and immigrants may not be immunized. Treatment includes (1) diptheria antitoxin within 48 hours of onset (after testing for sensitivity to antitoxin); (2) procaine penicillin G 600,000 units IM bid for 14 days (150,000 units/kg/day IV for 10 days for pediatric patients) or erythromycin 500 mg parenterally or po qid; (3) bedrest and supportive care; and (4) isolation until secretions are noncontagious. With some differences in regime, carriers are also treated.
Donovanosis: See Granuloma inguinale.
Dracunculiasis (Guinea worm disease) (Primarily West Africa [Nigeria] and Sudan; other areas of tropical Asia and Africa, Middle East, South America): Dracunculiasis is a tissue nematode infection with Dracunculus medinensis, the largest (up to one meter in length) filarial worm affecting humans. Infection occurs when small Cyclops (crustaceans) that contain larvae are ingested in contaminated fresh water such as that from large open wells. Infected persons are asymptomatic for approximately one year. Then, as the female worm reaches maturity, a papule, or in some cases, a sepinginous elevation of the skin develops - usually on a lower extremity. The papule progresses to a painful and pruritic blister, then an ulcer, and then the prolapsed uterus of the worm becomes visible and on contact with water releases larvae in a milky fluid. After repeated emptying, the worm dies and can then be slowly pulled forth and wound around a stick over a period of several weeks. Metronidazole 250 mg po tid for 10 days is used as an adjunct to mechanical removal. In most cases one to two worms emerge/year. Most people with dracunculiasis are incapacitated for about a month. Secondary bacterial infections are the most common complication.
Ebola hemorrhagic fever and Marburg hemorrhagic fever: See full discussion of HFs and full discussion of Ebola and Marburg HFs (Central Africa): Incubation of Ebola and Marburg HFs ranges from 3-16 days. Both Ebola and Marburg HFs are caused by viral infections characterized by sudden onset of fever, chills, severe headache, and myalgia. On about the fifth day of illness, a maculopapular rash may appear - most prominently on the trunk (the rash may eventually desquamate); along with pharyngitis, chest pain, abdominal pain, nausea, vomiting, diarrhea, and hemorrhagic symptoms, e.g., bleeding mucosal membranes. Symptoms may increase in severity and include jaundice, pancreatic inflammation, rapid weight loss, prostration, delirium, shock, hepatic failure, massive hemorrhaging, and multi-organ failure. Case fatality rates for for Ebola HF range from 50-90% and for Marburg HF around 25%. Treatment is supportive as discussed in the full discussion of hemorrhagic fevers.
Echinococcosis (Hydatid disease): See full discussion (Most of the world; endemic in South America, North Africa, Middle East, Southern Europe - especially in areas where sheep are raised). Echinococcosis or hydatid disease is a tapeworm infection that often is asymptomatic, especially in the lengthy early stages. Echinococcus embryos trapped in various organs (especially the liver or lung) develop into hydatid cyst(s), which grow and eventually cause dysfunction according to the function or area of the organ(s). Surgical excision of the cyst remains the treatment of choice. Albendazole is given pre and post-operatively. Drug treatment includes albendazole or mebendazole or praziquantel - all with poor cure rates.
Elephantiasis: See filariasis.
Encephalitis (see Arbovirus encephalitis): Causes of encephalitis among refugees and immigrants include arborvirus infections (mosquito or tick-borne - especially cerebral malaria), trypanosomiasis, relapsing fever, trichinosis, cysticerosis, toxocariasis, and angiostrongyliasis.
Enteric fever: See typhoid fever.
Enterobiasis or Pinworm infection (Worldwide; most common helminthic infection in Western Europe and U.S.): Enterobiasis is a nematode infection of the intestinal tract caused by Enterobius vermicularis eggs which are ingested via contaminated food or soiled hands. Manifestations/associated problems include perianal pruritis, vulvovaginitis in prepubertal girls, and secondary enuresis and urinary tract infection. Treatment is with mebendazole single dose of 100 mg po, repeated in 2 weeks or albendazole single dose of 400 mg po, repeated in 2 weeks (Not FDA approved for this use).
Enterovirus exanthems: Enterovirus exanthems are rashes secondary to gastrointestinal tract infection by picornaviruses, including poliovirus, coxsackieviruses, and echoviruses.
Eosinophilic myeloencephalitis: See Gnathostomiasis.
Escherichia coli (Woldwide): E. coli are gram negative motile or nonmotile short rods that are a common cause of urinary tract and epidemic diarrheal diseases.
Familial Mediterranean fever (Mediterranean area, primarily among persons of Sephardic Jewish, Armenian, and Arab ancestry): Familial Mediterranean fever (FMF) is an inherited disorder whose etiology is unknown. FMF is characterized by recurrent episodes of fever, abdominal pain, peritonitis and/or pleuritis or other chest pain; and in some cases, amyloidoses, arthritis, and skin lesions (especially on lower extremities). Onset is usually between the ages of 5 and 15 years. Treatment of acute attacks is supportive. Prophylactic treatment with colchicine 0.6 mg po tid or bid is effective. Fascioliasis: See trematodes, liver-dwelling.
Filariasis: See full discussion (Distribution given below). The filarial parasites are tissue-dwelling roundworms whose microfilarial (mf) larvae are transmitted by several species of mosquitos or flies. The most problematic forms of filariasis are (1) Bancroftian filariasis and Malayan filariasis (much of the tropical and subtropical world between the Tropics of Cancer and Capricorn) which involve the lymphatic system and result in elephantiasisis; (2) loiasis or loa loa (tropical Africa) in which worms live in subcutaneous tissue; and (3) Onchocerciasis (tropical Africa and to a lesser extent Central and South America) which causes river blindness and skin disorders. Treatment in most cases is effective only against the mf, hence the infection continues and repeated treatment (with ivermectin and/or DEC) may be necessary.
Fluke (trematode) infections: See trematodes below. These are divided according to primary system involvement and there is a complete discussion of schistosomiasis or blood flukes in a separate file.
Giardiasis: See full discussion (Worldwide): Giardiasis or giardia is caused Giardia lamblia, a protozoan transmitted via water or food contaminated with human feces; and is also transmitted sexually (usually anal-oral). Many infected persons are asymptomatic, while others experience diarrhea as the primary symptom. Diarrhea ranges from one loose stool/day to frequent copious watery stools, may be acute or chronic, and continuous or intermittent (with bouts of constipation). When copious, stools often contain mucous, but seldom blood, and are greasy/steatorrheic, frothy and foul-smelling. Other common symptoms are abdominal pain, nausea and vomiting, anorexia, flatulence, fatigue, and weight loss. The acute phase may last days or weeks, with resolution usually spontaneous. Some patients develop chronic giardiasis, which persists for many years. Metronidazole 250 mg. tid x 5 days is a common treatment. Alternatives include furazolidone, albendazole, and paramomycin. Empiric treatment is common.
Gibralter fever: See Brucellosis.
Gnathostomiasis (China, Japan, Southeast Asia, Pacific Islands): Gnathostomiasis is a tissue nematode (roundworm) infection with Gnathostoma spinigerum following ingestion of undercooked fish or fowl. Initial symptoms are nausea, vomiting, right upper quadrant abdominal pain, hepatomegaly, fever, and eosinophilia; followed 2-4 weeks later by diffuse painless, pruritic subcutaneous swelling which may migrate, wax and wane, or appear as serpiginous. Swelling is due to migration of the immature worm, and usually is found on an arm or leg, but may also occur in the eyelid (with associated ocular symptoms) or may also affect visceral organs. Eosinophilic myeloencephalitis occurs when the worm migrates along a large nerve trunk resulting in nerve root pain, paralysis, severe headache, and/or signs of cerebral hemorrhage. Treatment includes surgical removal + albendazole 400 mg po for 21 days (not FDA approved and not highly effective).
Granuloma inguinale or Donovanosis (Tropics, especially Southern India, Southern Africa, Pacific Islands, Papua, New Guinea, Caribbean Islands): Granuloma inguinale is a sexually transmitted disease caused by Calymmatobacterium granulomatous and characterized by an initial papule on the penis or labia. The papule ulcerates and develops into a painless granulomatous (beefy red and friable) raised area that spreads. Secondary anaeorobic infections are common and result in pain and foul-smelling drainage. Extension to the inguinal region may produce swelling similar in appearance to bubos. Early lesions of granuloma inguinale may be mistaken for syphilis, ulcerative stages mistaken for lymphogranuloma venereum, and the granulomatous tissue may be mistaken for carcinoma. Treatment is with TMP/SMX, azithromycin, tetracyclines, or newer quinolones.
Guinea worm: See Dracunculiasis.
Hantavirus pulmonary syndrome: See full discussion of HFs (North America, especially Southern; South America, especially Andes): Hantavirus infection is thought to occur through inhalation of infected rodent droppings. Incubation ranges from 7-28 days. In Latin America, hantaviruses cause HFs as described in the full discussion of HFs; and in the U.S., cause the hantavirus pulmonary syndrome (HPS). HPS is characterized by flu-like febrile illness that rapidly progresses to shock and adult respiratory distress syndrome with thrombocytopenia, hemoconcentration, and leukocytosis. Treatment is supportive as discussed in hemorrhagic fevers. Ventilation may be necessary within 24 hours of onset.
Hemorrhagic fevers (HFs): See full discussion of HFs. The major HFs include hemorrhagic fever with renal syndrome, hantavirus pulmonary syndrome, South American HFs, Lassa HF, Marburg and Ebola HFs, Kyasanur Forest HF, Omsk HF, Crimean-Congo HF, Chikungunya fever, dengue fever and HF, and Rift Valley fever (distribution is noted in the full discussion). The viral hemorrhagic syndrome (VHS) results from widespread increased permeability of microvasculature. Depending on the severity of vascular instability and decrease in platelet function, presentation may range from mild to severe illness; and hemorrhagic manifestations are not always apparent. A common course of illness begins with an abrupt onset of fever, myalgia, cutaneous flushing, and conjunctival suffusion. Within several days, the patient's condition worsens to include syncope, photophobia, headache, hyperesthesia, abdominal pain, nausea/vomiting, anorexia, and prostration. Treatment is primarily supportive, except that Lassa fever, South American HFs, and possibly Crimean-Congo HF and Rift Valley HF may be treated with a slow infusion of IV ribavirin.
Hemorrhagic fever with renal syndrome: See full discussion of HFs (Europe, Russia, East China, and Korea): Hemorrhagic fever with renal syndrome is caused by hantavirus. Incubation ranges from 9-35 days. Severity of the illness varies, mild or subclinical infections common. More severe cases are characterized by a febrile stage lasting 3-5 days with abrupt onset of fever, headache, photophobia, blurred vision, facial flushing extending to neck and shoulders, conjunctival petechiae, periorbital edema, pharyngeal injection and/or petechiae, axillary petechiae, lumbar back pain and CVA tenderness lasting 3-5 days. The illness may gradually resolve after this febrile stage or a hypotensive stage may begin as the temperature falls. The hypotensive stage is characterized by decreased blood pressure, tachycardia, and sometimes shock. Proteinuria, thrombocytopenia, leukocytosis, oliguria occur, as does renal failure in some cases. Renal function returns as the oliguric phase resolves and the polyuric phase ensues. Electrolyte imbalances and dehydration may occur in the polyuric phase. Disseminated intravascular coagulation may occur relatively early in the course of illness. Treatment is supportive as discussed in Hemorrhagic Fevers.
Hepatitis: Hepatitis B surface antigen carrier rates in the tropics are > 40 times greater than in the West. Persons from China and Southeast Asia are at highest risk and perinatal transmission is common.
Histoplasmosis (Africa, Americas, East Asia, Australia): Best known in the West as an opportunistic infection of HIV, histoplasmosis is found among immigrants as the classic small-form histoplasmosis (primarily pulmonary) and as African histoplasmosis (primarily bone and cutaneous). Treatment is with amphotericin B initially, and itraconazole or fluconazole are used for maintenance therapy.
HIV/AIDS: HIV/AIDS is found world-wide, and is especially common in sub-Saharan Africa, Southeast Asia, and India. Heterosexual transmission is common in these areas. Readers are referred to the CDC and other current sources of information (See links).
Hookworm: See full discussion (Most tropical and subtropical areas of the world). An important cause of anemia, hookworms are intestinal parasites (nematodes, including Ancylostoma duodenale, Unicinaria stenocephala, and Necator americanus) whose larvae are transmitted from soil through the skin. Incubation is 2-8 weeks. Most people (with small parasite loads) are asymptomatic. Entry points are sometimes pruritic. Higher loads result in anorexia or increased appetite, abdominal discomfort, weight loss, nausea and vomiting, diarrhea and/or constipation, and anemia. Respiratory symptoms occur in a few patients. Infants and children may experience severe anemia, protein deficiency, and developmental delays. Treatment is with mebendazole, albendazole, or pyrantel pamoate. None of these are safe in pregnancy and neither mebendazole nor albendazole should be given to children under 1 year of age. The anemia should be treated with ferrous sulfate.
Hydatid disease: See echinococcus or full discussion.
Hymenolepiasis (Americas, Mediterranean, Near East, India, Australia): Hymenolepsis nana is the smallest and most common tapeworm (cestode) parasitizing humans. H. nana is spread by the fecal-oral route and is especially common in institutions. Most infected persons are asymptomatic, but very high loads may produce anorexia, abdominal pain, and diarrhea. Treatment is with praziquantel 25 mg/kg in one po dose.
Junin hemorrhagic fever: See South American hemorrhagic fevers or go to full discussion of HFs.
Kala-azar: See leishmaniasis (visceral) below or full discussion.
Katayama fever: See schistosomiasis or full discussion..
Kyasanur Forest hemorrhagic fever: See full discussion of HFs (India). Kyasanur Forest HF is caused by a tick-borne flavivirus and currently is found only in the Mysore State of India. Incubation is 3-8 days. The illness is characterized by sudden onset fever and headache, followed by back and extremity pain, bradycardia, lymphadenopathy, conjunctival injection, palantine injection, petechiae, and other hemorrhagic signs. Meningoencephalitis is relatively common. Treatment is supportive as described in the full discussion of hemorrhagic fevers.
Lassa hemorrhagic fever: See full discussion of HFs (West Africa, including Nigeria): Lassa fever is caused by hantavirus. The incubation period ranges from 7-21 days. Presentation of Lassa fever varies. Common early symptoms are gradual onset of fever, malaise, headache, and abdominal pain. Other symptoms are conjunctivitis, facial swelling, sore throat, non-productive cough, retrosternal pain, nausea, vomiting, diarrhea, back pain, and myalgia. Respiratory rate, temperature, pulse rate are increased and blood pressure decreased. Neurological symptoms may also occur, including hearing loss, tremors, and encephalitis. Hemorrhagic manifestations (not usually evident) may include mucosal bleeding and, less frequently, conjunctival, gastrointestinal, or vaginal bleeding. Severe infections produce hemorrhagic manifestations, pleural effusions, and shock. Pregnant women are more likely to die than are others. Some degree of deafness occurs in about 30% of patients. Treatment is supportive and also includes ribavirin as discussed in the full discussion of hemorrhagic fevers.
Leishmaniasis: See full discussion or brief discussions of the various types (visceral, cutaneous, mucocutaneous) (East and North Africa, Middle East, Southern Europe, Central, South, and East Asia, South America, West Mexico): The protozoal parasite species Leishmania is transmitted by sandflies. Major types of leishmaniasis include visceral leishmaniasis or kala-azar, cutaneous leishmaniasis, and mucocutaneous leishmaniasis (espundia). Incubation is usually 2-6 months or longer and relapse may occur as many as 10 years after first episode. Signs and symptoms vary according to the type of leishmaniasis. See visceral leishmaniasis, cutaneous leishmaniasis, and mucocutaneous leishmaniasis (espundia).
Leprosy: See full discussion (Tropical and sub-tropical Africa, Asia, Pacific Islands, South America, Central America, and Mexico): Leprosy is caused by the acid-fast rod Mycobacterium leprae which is transmitted probably via the respiratory route through prolonged exposure in childhood. Incubation is usually 2-5 years; and up to 20 years. There are two basic types of leprosy: lepromatous leprosy (LL) and tuberculoid leprosy (TL) and either of these may be classified as borderline or indeterminate. Most initial infections involve few symptoms and spontaneous recovery is common with a minority of patients developing clinical disease. LL is a progressive malignant process including skin lesions/changes; as well as nerve damage and disability. TL is not as disabling as LL and includes skin lesions and nerve damage. Borderline leprosy may have features of both LL and TL, and may evolve into either form. Indeterminate leprosy is manifested by one or several macules or poorly defined skin lesions, that may heal spontaneously, remain stable, or progress to forms described above. Multi-drug therapy is the current accepted standard for all types of leprosy, and for LL generally includes dapsone, clofazamine, and rifampin daily for at least 2-3 years until all biopsies are negative for acid-fast bacilli. Patients with indeterminate or tuberculoid leprosy may be treated with dapsone and rifampin as above for 6-12 months, followed by dapsone alone for a total of at least two years of therapy. Antigen-antibody complex reactions (to therapy) are common and are treated with prednisone or thalidomide.
Leptospirosis: See full discussion (Worldwide, especially tropical areas of Latin America and Southeast Asia): Leptospirosis is a spirochette (Leptospira interrogans) infection transmitted primarily through exposure to water contaminated with urine from infected animals. Leptospirosis varies from asymptomatic to a severe or fatal illness. There are two common forms (anicteric and icteric or Weil's syndrome). Anicteric leptospirosis is the more common and milder form, and often is biphasic, with the first phase characterized by sudden onset high fever with chills, headache, conjunctival suffusion, cough and pulmonary chest pain, abdominal pain, nausea and vomiting, and myalgia. The illness may resolve after about one week with no further manifestations; or, after one to three days, recur with milder and more varied symptoms than in the first phase - except that aseptic meningitis may occur. Icteric leptospirosis or Weil's syndrome is the more severe form and is characterized by symptoms as described above (except not usually biphasic); and after about one week, the development of decreased renal function, pulmonary complications, jaundice, and/or hemorrhagic manifestations. Treatment includes antibiotics (doxycycline, penicillin, or others) and support.
Loiasis or loa loa: See full discussion or summary of filariasis.
Lyme disease (North America, Europe, Asia): Lyme borreliosis is a tick-borne spirochete, and though Lyme disease often considered (in the U.S.) as a North American illness, is also found in Europe and Asia. There also are similar tick-borne illnesses. Lyme disease occurs in three stages: (1) Early localized infection is characterized by erythema migrans, i.e., papule or macule expanding to large annular lesion with clearing center or center that becomes indurated or necrotic. (2) Early disseminated infection is characterized by fever with chills, secondary (and smaller) lesions, headache, stiff neck, myalgias, arthralgias, and malaise and fatigue; other neurological signs, and sometimes cardiac problems may also develop. (3) Late persistent infection is characterized by the development of arthritis, chronic synovitis, and other musculoskeletal problems. Central and peripheral nervous system disorders also occur, as well as skin lesions such as acrodermatitis chronicum atrophicans which presents as discoloration and swelling of a distal extremity progressing to a condition resembling localized scleroderma. Diagnosis of Lyme disease is based on exposure and presence of specific symptoms (erythema migrans + at least one late manifestion + laboratory confirmation - usually antibodies by ELISA). Treatment is with oral antibiotics (doxycycline or amoxicillin or cefuroxime axetil or erythromycin for 10-60 days, depending on severity/extent of illness) or, if neurological involvement, with IV antibiotics.
Machupo hemorrhagic fever: See South American hemorrhagic fevers or go to full discussion of HFs.
Maduromycosis: See mycetoma below.
Malaria: See full discussion (Tropical Africa, Asia, South and Central Americas; East China, Middle East): Malaria is caused by the protozoas Plasmodium falciporum, P. vivax, P. ovale, and P. malariae and is transmitted by mosquito bite, parenteral injection, or congenitally. Malaria is usually characterized by sudden onset of high fever, sweating, chills, uncontrollable shaking, headache, and splenomegaly. Fever tends to wax and wane in 48-72 hour cycles, though cycles may be irregular, especially with infection by P. falciporum. Onset may also be insidious, with less dramatic symptoms such as fever, headache, dyspnea, abdominal pain, nausea, diarrhea, myalgias, and splenomegaly. P. falciporum may cause parasitemia resulting in a life-threatening condition characterized by hemolysis, jaundice, anemia, acute renal failure, and hemoglobinuria. Cerebral malaria, also life-threatening, is characterized by gradual onset of severe headache, drowsiness, delerium, and coma. Seizures may also occur and are most common in children. P. faciporum causes death in as many as 25% of untreated cases. Treatment depends on the organism, immune status of the patient, and severity of the attack. Oral chloroquine is a mainstay of treatment except for infection with chloroquine-resistant P. falciporum. P. falciporum presents the greatest challenge because of severity of attacks as well as the existence of multidrug (especially chloroquine)-resistant strains. Combination drug treatment is common, e.g., mefloquine combined with artesunate for multidrug-resistant strains as described in the full discussion.
Malnutrition: Though not a communicable disease, malnutrition bears mention here as a common problem among refugees and, to a lesser extent, immigrants. We expect at some time to have a full discussion of malnutrition. Malnutrition may be the result of decreased intake of one or all food groups or to decreased absorption. Metabolic disorders, diarrheal illnesses, or the indirect effects of chronic illnesses are common causes of decreased absorption. Malnutrition has long-term deleterious effects on the person suffering from decreased intake or absorption; or on the fetus or on the children of the person with malnutrition. Loss of intellectual potential, incomplete physical or mental development, and vulnerability to illness are among the long-term effects of malnutrition. Basic types of malnutrition include marasmus, protein malnutrition (Kwashiorkor), and cachexia. Though not often a problem among refugees, obesity may also be viewed as malnutrition. Marasmus is due to inadequate caloric intake and is characterized by failure to gain weight, then weight loss with resultant emaciation. Loss of subcutaneous fat causes poor turgor and wrinkling of skin. With advanced marasmus, the basal metabolic rate slows with resulting decreased vital signs and profound weakness. Children with marasmus often are the subject of the most dramatic photographs of Somali, Ethiopian, and other children of famine. Kwashiorkor or protein-calorie malnutrition (PCM) may be due to inadequate intake or absorption (or loss) of protein. Kwashiorkor is more common and the clinical picture is less dramatic than the emaciation of marasmus. Initially, inadequate protein causes lethargy or irritability. As the condition progresses, anorexia develops, weakness increases, muscle tissue decreases, and growth is retarded. Hepatomegaly occurs, kidney function decreases, and cardiac function is impaired. Edema is common and may mask other aspects of the disorder. Skin changes include dermatitis, changes in pigmentation, and changes in hair. Typically, hair is sparse, thin, and often streaked with red or gray color. Immune function is decreased and infection is common and often is the cause of death. Treatment of marasmus and Kwashiorkor includes fluid replacement, gradual protein and calorie replacement (fats are poorly tolerated in Kwashiorkor), and correction of vitamin and other deficiencies. A concern in both refugee camps and countries of second asylum, is the tendency of parents to overfeed when food becomes available. Cachexia is a metabolic disorder marked by general ill health and malnutrition, with weakness and emaciation; and is common in cancer, AIDS and other severe illnesses. In contradistinction to anorexia or starvation, in cachexia, there is approximately equal loss of fat and muscle, significant loss of bone mineral content, and cachexia does not respond to nutritional supplements or increased intake.
Malta Fever: See Brucellosis.
Marburg and Ebola hemorrhagic fevers (HFs): See Ebola HF or full discussion of HFs.
Mediterranean fever: See Brucellosis, Gibralter fever, Cyprus fever, undulant fever, and typhomalarial fever.
Melioidosis (Southeast Asia): Melioidosis is infection by Pseudomonas pseudomallei (gram negative bacillus) with symptoms of fever, pulmonary infection that may range from bronchitis to necrotizing pneumonia. Acute septicemic melioidosis is most common among debilitated persons. Focal suppuration (nodule, lymphangitis, lymphadenopathy) results from inoculation through a break in the skin. Chronic suppurative disease may involve virtually any body system. Recrudescence may occur many years after the initial infection. Treatment is according to susceptibility. Common antibiotics used are TMP-SMX (not in Thailand), Augmentin, doxycycline, and cephalosporins.
Meningitis, chronic and recurrent, is common worldwide, often as a complication of communicable diseases caused by a variety of pathogens as follows: (1) Bacterial causes include incompletely treated suppurative meningitis, parameningeal infection, Lyme disease, mycobacterium tuberculosis, syphilis; and less commonly actinomycosis brucellosis, leptospirosis, nocardial infection, and Whipple's disease. (2) Fungal infections with the potential to cause meningitis include aspergillosis, blastomycosis, cryptococcus, coccidiomycosis, candidiasis, histoplasma, and sporotrichosis. (3) Protozoal causes include toxoplasmosis and trypanosomiasis. (4) Helminthic causes include angiostrongyliasis, cysticercosis, gnathostomiasis, and trichinosis. (5) Viral causes include echoviral infections, herpes, HIV, lymphocytic choriomeningitis, and mumps. Viral or aseptic meningitis is characterized by sudden onset of fever and signs and symptoms of meningeal involvement (headache, neck stiffness, irritability/malaise, and sometimes rash and nausea and vomiting (from Chin, 2000; Koroshetz & Swartz, 1998).
Meningoencephalitis is relatively common worldwide and in some cases occurs as a complication of communicable diseases. Viruses are the most common pathogen, especially enteroviruses, but also arboviruses, herpesviruses, and other pathogens in illnesses including African trypanosomiasis, amebiasis, angiostrongyliasis, candidiasis, Chagas' disease, cryptococcosis, cytomegalovirus, dengue fever, hemorrhagic fevers, herpes, listeria, toxoplasmosis, and others. Young age and immunocompromise increase the risk of meningoencephalitis.
Mucocutaneous Leishmaniasis (Espundia): See full discussion of leishmaniasis (Latin America): Mucocutaneous leishmaniasis is a sequela of new world cutaneous leishmanaiasis and results from spread to the nasal or oral mucosa, with naso-oropharyngeal symptoms sometimes appearing several years after resolution of the primary lesion(s) and sometimes while the primary lesions are present. Manifestations include chronic nasal symptoms, especially of the anterior nasal septum, progressing to naso-oropharyngeal destruction. Secondary bacterial (or fungal) infections and associated problems are common. Treatment is difficult and cure rates decrease with advanced disease. Treatment is as for cutaneous leishmaniasis.
Mycetoma - also known as maduramycosis (Worldwide, especially tropics): Fungal infection, that begins as a small abscess, papule, or nodule and progresses to localized larger and multiple abscesses with sinuses; and ultimately to destruction of deep tissue, fascia, and bone. The usual route of infection is via a break in the skin (commonly from a thorn wound) through which the fungus is implanted from contaminated soil or plant. Secondary bacterial infection may occur. The foot is the most common site of infection, leading to "madura foot." Eumycetoma is infection due to filamentous fungi and is resistant to treatment. Actinomycetoma is infection due to actinomycetes and treatment is often effective. Treatment is with long-term combination therapy, e.g., streptomycin + dapsone or TMP/SMX. Surgical debridement + long-term ketoconazole or itraconazole is also used in treatment.
Myiasis (Worldwide - uncommon in countries of second asylum): Myiasis is the infestation of a wound with larvae of flies.
Naegleria infection (Worldwide): Naegleria fowleri (a protozoal) infection is the cause of amebic meningoencephalitis, which currently is rare. There are two forms: (1) acute and often fatal CNS infection in otherwise healthy persons and (2) granulomatous infection in immunocompromised persons. Meningoencephalitis is also related to other illnesses. See meningoencephalitis above.
Nematode infections: See angiostrongyliasis, anisakiasis, ascariasis, capillariasis, dracunculiasis, enterobiasis, filariasis, gnathostomiasis, hookworm, strongylodiasis, trichostrongyliasis, trichuriasis (some with full discussions).
Nutritional deficits: See malnutrition.
Omsk hemorrhagic fever: See full discussion of HFs (Russia): Omsk HF is caused by a tick-borne flavivirus and currently is found only in Russia. The illness is characterized by sudden onset fever and headache, followed by back and extremity pain, bradycardia, lymphadenopathy, conjunctival injection, palantine injection, petechiae, and other hemorrhagic signs. Incubation is 3-8 days. Treatment is supportive as described in the full discussion of HFs.
Onchocerciasis (River blindness): See filariasis summary or full discussion.
Opisthorchiasis: See trematodes (biliary tract-dwelling) below.
Paracoccidioidomycosis (South American Blastomycosis) (Mexico, Central and South America): Paracoccidioidomycosis is an ulcerating mycotic infection (caused by Paracoccidioides brasiliensis) usually first involving the naso-oropharynx, and later adjacent areas, including the skin and face; and progressing to the lungs, liver, and elsewhere in the GI system. Lymphadenopathy, pulmonary symptoms, and cachexia may occur. Treatment is with itraconazole unless the illness is serious enough for hospitalization, in which case, IV amphotericin B is given, followed by itraconazole.
Paragonimiasis: See trematodes, lung-dwelling below.
Parastrongyliasis (Caribbean, Southeast Asia, Pacific Islands): Parastrongyliasis includes several distinct nematode (roundworm) infections caused by Parastrongylus sp. as follows. (1) Nematode (rat lungworm) infection with P. cantonensis that often is subclinical. Larvae migrate to the CNS and may cause eosinophilic meningoencephalitis. Symptoms may include severe headache (most common symptom), stiff neck, low grade fever, nausea, vomiting, abdominal discomfort, paresthesias of trunk and extremities, and other neurologic signs, including unilateral facial paralysis. The disease is usually self-limiting. Treatment is supportive, and includes corticosteroids, spinal taps, and analgesics. Antihelminthics are not used because of host reaction to dead worms in the CNS. (2) Nematode infection with P. costaricensis of the gastrointestinal tract with manifestations including abdominal and flank pain, fever, malaise, anorexia, nausea, vomiting, and weight loss. Treatment is directed toward supporting the patient. Surgery is sometimes necessary. Corticosteroids are not effective and antihelminthic drugs excite the worms with deletorious effects on the patient.
Pemphigus disorders (foliaceus, vulgaris, etc.) (Worldwide, uncommon): Pemphigus disorders are immunologically mediated skin diseases characterized by blistering or formation of vesicles at various skin depths, depending on the specific disorder. Systemic glucocorticoids and immunosuppresive agents are used to treat severe cases, while mild cases sometimes respond to topical steroids.
Pertussis or whooping cough (Worldwide): Most refugees and immigrants arrive in the U.S. with at least the first series of immunizations. However, not all records are accurate and some small risk exists for pertussis and other such illnesses. The infectious agent is Bordetella pertussis. Pertussis occurs in three stages: (1) The catarrhal stage is manifested by gradual onset of slight fever, dry cough, coryza, sneezing, malaise, and anorexia. (2) The paroxysmal stage begins 10-14 days after onset of symptoms and lasts 4-6 weeks. This stage includes the characteristic whooping cough (paroxysmal violent coughing spells with respiratory distress and without intervening inhalation and then a high-pitched inspiratory crowing whoop). Mucous is copious, clear, and tenacious; and vomiting may follow coughing. Coughing is most severe for the first 10-14 days of the paroxysmal stage and then severity gradually decreases. Paroxysms of coughing and the whoop are not always present in older children or adults. (3) The convalescent stage is marked by a chronic cough lasting as long as two years. Treatment includes respiratory isolation until the patient has received at least five days of a 14 day course of antibiotics; erythromycin (estolate form preferred) 50 mg/kg/day in 2-4 divided doses with a maximum of 2 gm/day for 14 days; supportive care is given in the hospital for younger and older patients. Cough suppressants are ineffective.
Pinta (mal de pinto, carate) (Rural areas of Latin America): Pinta is a spirochetal (Treponema carateum) skin infection characterized by a painless scaling papule with regional lymphadenopathy progressing to non-ulcerating maculopapular erythematous areas. Spread is by extension and by secondary lesions (pintides), which may be numerous. Pintides may be psoriatic or circinate in configuration. Initially the pintides are red, then slate blue, and then loss of pigmentation occurs, resulting first in brown areas, and eventually in mottled white skin. Lesions appear in various stages of development and are seen most commonly on the extremities and face. Pinta is decreasing in incidence and prevalence. The preferred treatment is 2.4 million units of IM benzathine penicillin G for adults and 1.2 million units for children.
Pinworms: See enterobiasis.
Plague (Worldwide, but primarily rural and lightly populated areas in undeveloped countries): Plague is an acute febrile zoonotic disease caused by Yersinia pestis, a microaerophilic coccobacillus of the family Enterobacteriaceae. Plague is transmitted primarily by flea (from rodents) bite, but also from direct inoculation through handling infected mammal carcasses or via the respiratory route from infected droplets from a patient with pneumonic plague. The most recent pandemic was in the late 19th and early 20th centuries and resulted in estimated 12,000,000 deaths. In recent years (1970s-1990s), most cases have been reported in Africa, Asia, and the Americas. There are three common forms of plague: bubonic (most common), pneumonic (most rapid and most frequently fatal), and septicemic - with the latter two either primary or secondary to metastatic spread. Plague is manifested by abrupt onset of high fever, severe headache, severe myalgias, prostration, and in some cases, delirium. The incubation period is 2-10 days. An ulcer may develop at the inoculation site. Lymphadenitis is followed by painful, draining bubo(s). Pneumonic plague produces fulminant pneumonitis with frothy bloody sputum and sepsis. Hematogenous spread or septicemic plague is characterized by rapid decline, coma, and purpura - hence the term "black plague." Treatment must be quickly instituted in all cases. IM streptomycin is the first line treatment, though IM or IV gentamicin is frequently used. IV or po tetracycline or doxycycline are also used.
Pneumonia: See anthrax, ascariasis, blastomycosis, coccidioidomycosis, histoplasmosis, HIV/AIDS, legionellosis, paragonimiasis, plague, psittacosis, Q fever, typhus, strongyloidiasis, tuberculosis. Note other, more common causes.
Poliomyelitis (Primarily on the Indian subcontinent and Africa - "on the verge of worldwide eradication" [Chin, 2000]): Poliomyelitis is caused by an enterovirus and in the great majority of cases, infection is asymptomatic. The types of symptomatic poliomyelitis are: (1) Abortive poliomyelitis is characterized by self-limited fever, headache, sore throat, nausea, vomiting, diarrhea, and constipation. (2) Nonparalytic poliomyelitis is characterized by meningeal signs (e.g., headache, stiff neck, irritabilty, nausea, vomiting), muscle spasms, and the constitutional signs noted under abortive poliomyelitis. (3) Paralytic poliomyelitis may develop during the febrile stage of illness. There are two types of paralytic poliomyelitis: (1) Spinal involves weakness or paralysis of muscles ennervated by spinal nerves. Bulbar involves weakness or paralysis of muscles ennervated by cranial nerves IX and X, as well as respiratory and vagal centers. Development of paralysis is decreased by strict bedrest. Treatment otherwise, is supportive.
Psittacosis (Worldwide): Psittacosis is Chlamydia psittaci infection contracted from infected birds. Psittacosis is characterized by rapid onset of fever, chills, headache, dry cough, myalgia; and later development of dyspnea and atypical pneumonia. Complications include endocarditis, hepatitis, or neurologic complications. Except for contact with birds, psittacosis is indistinguishable from viral, mycoplasmic, or other atypical pneumonias. Treatment is with tetracycline or erythromycin.
Q fever (Worldwide): Q fever is a rickettsial zoonosis (infection with gram negative Coxiella burnetii) contracted primarily from inhalation of dust contaminated by infected animals, especially sheep, cattle, and goats; and also other mammals. Other routes of infection include contact with milk and tissue from infected animals. Manifestations of acute Q fever include fever, fatigue, headache, cough, abdominal pain, nausea, diarrhea, and myalgia. Pneumonia develops in a small number of patients. Other complications are hepatitis, pericarditis, myocarditis, and meningoencephalitis. Hepato/splenomegaly and endocarditis are common in chronic Q fever. Endocarditis is frequently associated with purpuric rash, renal insufficiency, stroke, and heart failure. Treatment of acute Q fever is with doxycycline or a quinolone. Chronic Q fever requires combination therapy such as rifampin and doxycycline.
Relapsing fevers (Louse-borne relapsing fever [LBRF] is a public health problem primarily in the highlands of Ethiopia; while tick-borne relapsing fever [TBRF] has a much wider distribution): RFs are spirochetal infections with Borrelia sp. (gram negative helical bacteria) and are characterized by recurrent episodes of fever and apyrexia. Manifestations of both LBRF and TBRF are sudden-onset of fever, chills, headache, tachycardia, nausea and vomiting, arthralgia, myalgias, and petechial rashes. Hepatosplenomegaly is common and confusion may occur. Conjunctival injection, epistaxis, cough, and slight hemoptysis may also occur. Symptoms last for 3-10 days, when there is a crisis (>fever and severity of other symptoms), followed by recovery and relapse in about 7-14 days. There are one to two relapses in untreated LBRF and three to ten relapses in untreated TBRF. LBRF is treated with a single dose of oral erythromycin, tetracycline, doxycycline or chloramphenicol; or single parenteral dose of the preceding medications or penicillin G. TBRF is treated with a seven day course of the same medications. Jarisch-Herxheimer reactions to treatment are common (acute febrile reaction with headache and myalgia).
Rickettsioses (Worldwide): The rickettsioses are febrile exanthematous illnesses caused by arthropod carried rickettsiae. Rickettsioses include the typhus group, spotted fever group, Q fever, trench fever, and erlichiosis. See Boutonneuse fever, Q fever, spotted fevers, trench fever, and typhus.
Rift Valley fever: See full discussion of HFs (Africa, especially Central, Egypt): The Rift Valley fever (RVF) virus is transmitted by mosquito or perhaps other blood-sucking insect bite; and by exposure to body fluids or meat of infected animals. The incubation period is 3-5 days. Most people with RVF have no symptoms or a mild febrile illness with liver abnormalities. Others, however, develop a classic HF with weakness, fatigue, back pain, dizziness, and rapid weight loss. Retinal vasculitis occurs in about 10% of cases, and encephalitis occurs in a few patients. Though definitive research on treatment is lacking, treatment of severe cases may include the use of IV ribavirin as described in the full discussion of hemorrhagic fevers.
River blindness: See filariasis summary or full discussion.
Rotavirus (Worldwide): Rotavirus noninflammatory diarrhea is the most common cause of dehydrating diarrhea in children worldwide. Rotavirus gastroenteritis is more severe in children than adults. Treatment is supportive.
Salmonellosis (Worldwide): Salmonella sp. infections are well known in the Western world. In addition to the usual mild GI Salmonella sp. infections (more severe in the elderly), the more virulent Salmonella typhi causes typhoid fever.
Schistosomiasis or Bilharzia: See full discussion (Numerous areas of the world, especially Africa and Asia with variants and locations noted in the full discussion). Schistosomiasis is caused by Schistosoma sp. and encompasses several syndromes, not all of which are evident in all infected persons. Initial symptoms may include a pruritic, papular rash - most commonly in persons who do not live in endemic areas. Acute schistosomiasis (Katayama fever) occurs in primary infection 1-2 months after exposure to heavy parasite loads. Symptoms may include fever of several weeks duration, headache, urticaria, cough, hepatosplenomegaly, lymphadenopathy, diarrhea, and eosinophilia. Hematuria and dysuria occur in some infections. Symptoms tend to gradually diminish over several months, but may intensify as more eggs are deposited. Chronic hepatosplenic schistosomiasis is a consequence of eggs retained in tissue and prolonged infection - usually > 10 years duration. The liver may be large or small and firm with nodularity. Portal hypertension, splenomegaly, or esophageal or gastric varices may occur. Hematemesis and splenomegaly are common presenting symptoms, with normal liver function. Periportal fibrosis and portal hypertension is associated with glomerulonephritis (proteinuria, renal failure) and pulmonary hypertension (cor pulmonale). Granulomatous tissue in the bowel results in bloody diarrhea. The last (chronic) stage varies according to species, with some species primarily affecting the liver and intestines, and one species affecting primarily the urinary tract. In general, patients with chronic schistosomiasis tend to present in developed countries with lethargy, colicky abdominal pain, mucoid/bloody diarrhea, or dysuria and hematuria. Salmonella infection concurrent with schistosomiasis is common and is resistant to treatment unless the schistosomiasis is also treated. Complications include progression of liver, kidney, or other organ dysfunction for many years after transmission has been interrupted - especially with heavy infection and re-exposure. Central nervous system lesions occur, but rarely. Treatment is according to species: For S. haematobium and S. mansoni, praziquantel 20/kg po bid for one day; for S. japonica and S. mekongi, praziquantel 20/kg po tid for one day are the treatments of choice. S. mansoni may also be treated with oxamniquine in a single po dose (with food) of 15 mg/kg. S. haematobium in North and East Africa may be treated with metrifonate 7.5-10 mg/kg every other week for a total of 3 doses.
Scrub typhus: See typhus.
Shigellosis or bacillary dysentary (Worldwide): Acute diarrheal illness from Shigella sp. transmitted via fecal-oral route. Shigellosis is especially common in children. Treatment is supportive and focused on prevention of dehydration.
Sickle cell disease or sickle cell hemoglobulinopathies (Occurs primarily in people of African lineage, but also to a lesser extent among people from the Mediterranean area, Arabs, and Indians): Sickle hemoglobulinopathies are distortions (sickle shaped and rigid) in erythrocytes and a tendency for the sickled cells to clump together causing tissue ischemia and infarction. Clinical characteristics of the various sickle hemoglobulinopathies include:
Sickle cell diseases are well known as an African-American disease in the Western world, but may be missed among refugees or immigrants.
Sleeping sickness: See trypanosomiasis (African).
South American Blastomycosis: See paracoccidioidomycosis
South American hemorrhagic fevers: See full discussion of HFs, including Junin HF (Argentina), Machupo HF (Bolivia), and other HFs: Incubation in South American HFs ranges from 7-14 days. South American HFs are characterized by the gradual onset of fever, myalgia, and signs and symptoms as described above under general signs and symptoms. Thrombocytopenia, bleeding, and neurological dysfunction (confusion, tremors, and cerebellar signs) are common in South American HFs. Treatment is supportive and also includes IV ribavirin as discussed in the full discussion of hemorrhagic fevers.
Sporotrichosis (Worldwide): Sporotrichosis is a mycotic infection from inoculation of tissue with Sporothrix schenckii mold via an open wound - often associated with gardening activities. Sporotrichosis occurs in several forms, including (1) plaque sporotrichosis - a non-tender maculopapular granuloma at the site of inoculation; (2) lymphangitic sporotrichosis - a papule at the site of inoculation, followed by draining nodules along proximal lymphatic channels; (3) osteoarticular sporotrichosis - polyarticular arthritis that develops slowly and may include draining sinuses at joints. Treatment for plaque sporotrichosis is with potassium iodide or itraconazole. Treatment for lymphangitic or osteoarticular sporotrichosis is with a prolonged course of itraconazole and only about 50% of patients are cured.
Staphylococcus aureus infection (Worldwide): S. aureus produces an eneterotoxin that causes an acute and short-lived gastroenteritis, for which treatment is supportive.
Strongylodiasis (Most of the tropical world): Strongylodiasis is a nematode (roundworm) infection by Strongyloides stercoralis following larval penetration of the skin. A minority of infected persons are asymptomatic. Cutaneous manifestions may occur at the site of penetration (often feet), and include inflammation, serpiginous or urticarial tracts, and pruritis. Intestinal manifestations follow cutaneous, and include abdominal pain, nausea, flatulence, and diarrhea. Larval migration to lungs results in a variety of pulmonary symptoms, ranging from cough to pneumonia, pleural effusion, and miliary abscesses. Hyperinfection syndrome causes life-threatening CNS, cardiac, and wide-ranging gastrointestinal problems. Treatment is with ivermectin 200 mcg/kg/day po for two days. Albendazole and thiabendazole have also been used.
Subcutaneous mycotic infection: See mycetoma.
Syphilis (Worldwide): There are both venereal and endemic forms of syphilis, with the latter being primarily an illness of childhood caused by Treponoma pallidum ssp. endemicum (vs. T. pallidum ssp. pallidum, the infectious agent in syphilis) and occurring primarily in arid climates of the developing world. The prevalence of (endemic) syphilis infection among children <10 years of age ranges up to 19% among some nomadic groups in Africa. T. pallidum ssp. endemicum cannot be distinguished from T. pallidum ssp. pallidum in the laboratory.
Taeniasis: See tapeworms.
Tapeworms and cysticercosis (Worldwide, but endemic in certain areas): Tapeworm or cestode infections result from the ingestion of Taeniasis sp. eggs, often found in undercooked meat or excreted proglottids (segments) of the adult tapeworm. Depending on the species, adult tapeworms reach a length of eight meters and live as long as 25 years. The beef tapeworm (Taeniasis saginata) usually causes gastrointestinal discomfort and weight loss. Awareness of infection often is through discovery of proglottids in the stool. Manifestations of intestinal infection with the pork tapeworm (Taeniasis solium) are similar to those of the beef tapeworm. However, ingestion of food that is fecally contaminated with T. solium eggs results in cysticercosis. The symptoms of cysticercosis are caused by the presence of cysticeri (encapsulated larvae) and the resulting inflammatory reaction or space-occupying lesions. The incubation period is as long as five years. Manifestions are most commonly varied neurologic problems, including fever, headache, CVA, hydrocephalus, seizures, and other symptoms of increased intracranial pressure. Visual manifestations may be from increased intracranial pressure or a cyst in the eye. Cysts are also found in subcutaneous and muscle tissue. Treatment of intestinal tapeworms is with a single dose of praziquantel 5-10 mg/kg. Treatment of cysticercosis is with albendazole 5 mg/kg po tid for 8-30 days or praziquantel 20 mg/kg po tid for 14 days. Therapy may increase symptoms, in which case dexamethasone helps reduce distress. Also see echinococcosis and hymenolepiasis.
Tetanus (Worldwide): Tetanus is a neurological disorder caused by the neurotoxin elaborated by the ubiquitous soil-dwelling anaerobic bacillus Clostridium tetani. Infection occurs as a result of introduction of Clostridium spores into wounds. Early manifestations are stiffness of the neck and jaw (lockjaw), dysphagia, and irritability. Pain and tingling at the wound site, followed by regional fasciculations may also be presenting symptoms. Progression includes trismus (jaw muscle spasms), facial muscle rigidity, life-threatening airway /pulmonary muscle spasms, and neck, back, and abdominal muscle spasms, and tonic convulsions. Treatment is in an acute care facility and includes antibiotic therapy, antitoxin, and neurological, pulmonary, and other supportive care - often in a critical care unit. Illness does not confer immunity, hence immunization is included in treatment.
Thalassemias (Africa, Mediterranean, Middle East, Indian subcontinent, Southeast Asia): The thalassemias are inherited defect in globin chain production leading to hypochromic microcytic anemia. There are about 100 geographically unique mutations that produce thalassemia phenotypes. Interestingly, these are found in areas where Plasmodium falciporum malaria was or is endemic. The two most best known thalassemias are homozygous thalassemia major (Cooley's anemia) and heterozygous thalassemia minor. Thalassemia major is a life-threatening progressive hemolytic anemia. In untreated infants, the disease causes cardiac decompensation, profound weakness, expansion of marrow, thinning of bones, jaundice, organomegaly, and without treatment, death within about two years. Older patients have growth retardation, delayed puberty, diabetes, and heart disease. Laboratory findings include hypochromia, microcytosis, low hemoglobin, high serum iron, and high serum bilirubin. Regular blood transfusions are required to prevent or delay complications, but the transfusions themselves result in pathology. Thalassemia minor is characterized by chronic mild microcytic anemia, but no clinical symptoms.
Toxocariasis (Worldwide): Toxocariasis is the most common visceral larva migrans and is due to infection with the tissue nematode (roundworm) toxocara canis or T. cati. Toxocariasis is most common among children who eat feces-contaminated dirt. Most infections are small load and asymptomatic except for mild eosinophilia. Heavy worm loads, decreased immune competence, and other factors may lead to malaise, fever, cough and wheezing, hepatomegaly, anorexia, and weight loss. Ocular toxocariasis also occurs and usually leads to decreased vision. For symptomatic infections, the treatment of choice is diethylcarbamazine 6 mg/kg/day po tid for 10 days. Asymptomatic infections are not necessary to treat.
Toxoplasmosis (Worldwide): Toxoplasmosis is infection with Toxoplasma gondii, an obligate intracellular parasite (protozoan) usually transmitted by ingestion of undercooked meat or contaminated soil. There are two forms of toxoplasmosis, congenital and acquired. Congenital toxoplasmosis is associated with maternal infection shortly before conception, and is characterized by CNS involvement (convulsions, microcephaly or hydrocephaly, mental retardation and blindness) and liver involvement. Choreoretinitis is also common. Acquired toxoplasmosis is a well-known problem among immunocompromised persons, leading commonly to encephalitis, multiple organ infection, and death if not quickly treated. Among immunocompetent persons, toxoplasmosis is most commonly manifested by cervical lymphadenopathy, and less frequently by malaise, fatigue, fever, and headache. Choreoretinitis is common among both immunocompromised and immunocompetent persons. Treatment depends on immunocompetence and degree of symptomatology, and includes multi-drug regimes (commonly pyrimethamine + sulfadiazine or clindamycin) for 4-52 weeks; and in immunocompromised patients, lifelong maintenance therapy.
Trachoma (Worldwide; more commonly endemic in poor rural communities in developing countries and common among nomadic and semi-nomadic cattle-herder): Trachoma is a recurrent conjunctivitis beginning in childhood and caused by Chlamydia trachomatis. Trachoma is a major cause of blindness in developing countries. Childhood infections and reinfections result in bilateral follicular conjunctivitis, epithelial keratitis, and corneal vascularization. Conjunctival scarring results in ingrown/in-turned eyelashes and lid deformities that, in turn, cause corneal scarring. Secondary bacterial infections are common, resulting in further complications. Treatment is with po tetracycline or erythromycin, both 250 mg 6 times daily for 3-5 weeks. Doxycycline 100 mg po bid for 3-5 weeks is also a common treatment. A single dose of azithromycin 20 mg/kg po is also used.
Trematodes (flukes): See schistosomiasis above or full discussion and see trematode infection by affected system below. Trematodes, biliary duct-dwelling cause diseases including clonorchiasis and opisthorchiasis. (1) Clonorchiasis (China, Taiwan, Korea, Japan, Vietnam, and other areas of Asia) is a liver fluke (Clonorchis sinensis) infection of the biliary tract following ingestion of raw or pickled fish. Symptoms include upper abdominal pain, irregular high fever, lymphadenopathy, myalgia, and arthralgia. The condition may be chronic and include intermittent fever, vague abdominal symptoms, anorexia, and fatigue. Eosinophilia is pronounced. Treatment is with praziquantel 25 mg/kg po tid for one day. (2) Opisthorchiasis (Eastern Europe and Russia; Thailand) is a liver fluke infection of the biliary tract following ingestion of raw or pickled fish. Most infected persons have no significant symptoms. If the parasite load is high, symptoms may include upper abdominal pain, feeling that something is moving in the liver, hepatomegaly with tenderness, jaundice, intermittent fever, lymphadenopathy, myalgia, and arthralgia. The condition may be chronic and include intermittent fever, vague abdominal symptoms, anorexia, and fatigue. Eosinophilia is pronounced. Treatment is with praziquantel 25 mg/kg po tid for one day.
Trematodes, blood-dwelling (schistosomiasis or Bilharzia): See full discussion (Numerous areas of the world, especially Africa and Asia with variants and locations noted in the full discussion). Schistosomiasis is caused by Schistosoma sp. and encompasses several syndromes, not all of which are evident in all infected persons. Initial symptoms may include a pruritic, papular rash - most commonly in persons who do not live in endemic areas. Acute schistosomiasis (Katayama fever) occurs in primary infection 1-2 months after exposure to heavy parasite loads. Symptoms may include fever of several weeks duration, headache, urticaria, cough, hepatosplenomegaly, lymphadenopathy, diarrhea, and eosinophilia. Hematuria and dysuria occur in some infections. Symptoms tend to gradually diminish over several months, but may intensify as more eggs are deposited. Chronic hepatosplenic schistosomiasis is a consequence of eggs retained in tissue and prolonged infection - usually > 10 years duration. The liver may be large or small and firm with nodularity. Portal hypertension, splenomegaly, or esophageal or gastric varices may occur. Hematemesis and splenomegaly are common presenting symptoms, with normal liver function. Periportal fibrosis and portal hypertension is associated with glomerulonephritis (proteinuria, renal failure) and pulmonary hypertension (cor pulmonale). Granulomatous tissue in the bowel results in bloody diarrhea. The last (chronic) stage varies according to species, with some species primarily affecting the liver and intestines, and one species affecting primarily the urinary tract. In general, patients with chronic schistosomiasis tend to present in developed countries with lethargy, colicky abdominal pain, mucoid/bloody diarrhea, or dysuria and hematuria. Salmonella infection concurrent with schistosomiasis is common and is resistant to treatment unless the schistosomiasis is also treated. Complications include progression of liver, kidney, or other organ dysfunction for many years after transmission has been interrupted - especially with heavy infection and re-exposure. Central nervous system lesions occur, but rarely. Treatment is according to species: For S. haematobium and S. mansoni, praziquantel 20/kg po bid for one day; for S. japonica and S. mekongi, praziquantel 20/kg po tid for one day are the treatments of choice. S. mansoni may also be treated with oxamniquine in a single po dose (with food) of 15 mg/kg. S. haematobium in North and East Africa may be treated with metrifonate 7.5-10 mg/kg every other week for a total of 3 doses.
Trematodes, intestine-dwelling (Asia, Latin America, Africa) include several species ranging in size from 1 mm to 70 mm in length and causing gastrointestinal symptoms such as pain, nausea, vomiting, ascites, and obstruction; and cardiac problems including myocarditis. Treatment in most cases is with praziquantel 25 mg/kg tid for one day.
Trematodes, lung-dwelling cause paragonimiasis (Asia, Latin America, Africa): Paragonimus sp. are lung-dwelling (as well as other sites) trematodes. Infection is most frequently linked with ingestion of incompletely cooked or pickled shellfish. Paragonimiasis may persist for many years and thus present as acute or chronic illness - though chronic is the more common. Acute illness may include fever, cough, pleural effusion, and hepatosplenomegaly. Chronic paragonimiasis is characterized by cough, dyspnea, hemoptysis, brown-flecked sputum, and pleuritic chest pain. X-ray shows (depending on length of illness) diffuse or segmented infiltrates, nodules, cavities, ring cysts, and/or pleural effusions. Extrapulmonary infections may manifest with abdominal pain, diarrhea, and CNS symptoms. Treatment is with praziquantel 25 mg/kg tid for two days.
Trematodes, liver-dwelling cause fascioliasis (Worldwide where sheep and cattle are raised): Infection occurs after ingestion of contaminated water or water-dwelling vegetation, e.g., watercress. Acute fascioliasis is characterized by fever, abdominal pain (especially hepatic), nausea, diarrhea, and hepatomegaly. Cough may also occur. Liver enzymes and erythrocyte sedimentation rates are usually elevated, and anemia is common. Chronic disease results in a variety liver and gallbladder abnormalities. Bithionol 30-50 mg/kg orally qod for 10-15 doses is the treatment of choice as this is written. Bithionol is available in the U.S. from CDC. Triclabendazole in a single dose of 10 mg/kg may become the drug of choice when available in the U.S. (Rosenblatt, 1999).
Trench fever (Worldwide, decreasing incidence): Trench fever is thought to occur after bites from ectoparasites infected with Bartonella sp. (as in cat scratch fever). Trench fever is characterized by abrupt onset of fever, headache, myalgia, malaise, and often aseptic meningitis. Treatment is with prolonged antibiotic therapy, including erythromycin or azithromycin.
Treponematoses: See pinta, syphilis, and yaws.
Trichinosis (trichinella) (Worldwide): Trichinosis is a nematode (roundworm) infection with Trichinella sp. from ingestion of meat that contains cysts, especially undercooked pork or meat from a carnivore. Infection ranges from light and asymptomatic to heavy and life-threatening. Manifestations vary according to the life cycle of the worms: Initially there is malaise, nausea, cramping abdominal pain, and diarrhea. Gastrointestinal symptoms are followed in 1-6 weeks by fever, eosinophilia, periorbital and facial edema, conjunctivitis, dysphagia, dyspnea, cough, myalgia, and muscle spasms. Complications include meningitis and other neurological disorders, myocarditis, pneumonia, and nephritis. The current treatment of choice is mebendazole 300 mg po tid for 10 days (sometimes with prednisone to control symptoms).
Trichostrongyliasis (Africa and Asia): Trichostrongyliasis is a nematode (roundworm) infection with Trichostrongylus sp. (psuedo-hookworm) acquired by eating contaminated vegetables. Heavy infections result in mild anemia and eosinophilia, but infections are usually asymptomatic. Treatment is with pyrantel pamoate 11 mg/kg (maximum 1 gram) in one dose.
Trichuriasis (trichocephaliasis or whipworm) (Worldwide, especially tropical and subtropical areas): Trichuriasis is a nematode (roundworm) infection with Trichuris trichiura. Heavy infections may result in abdominal cramping, nausea, vomiting, flatulence, diarrhea, tenesmus, and weight loss. Mild infections are usually asymptomatic. Treatment is with albendazole single po dose of 400 mg (not FDA approved) or mebendazole 100 mg po bid for 3 days. Ivermectin is sometimes also used in combination with albendazole.
Tropical sprue (Tropical areas of the world): Tropical sprue is a malabsorption disorder of unknown etiology (possibly coliform organisms) that affects residents of or visitors to endemic or epidemic areas. Note that the disorder may occur years after leaving the tropics. Common manifestations are anorexia, abdominal distension, weight loss, and other findings consistent with malabsorption disorders; and decreased iron, folate, and B12. Treatment is with folate, B12, and 2-4 weeks of antibiotic therapy (sulfonamide or tetracycline with folic acid).
Tropical ulcer (correctly termed cutaneous leishmaniasis; and also known as oriental sore, tropical sore, Delhi boil, Allepo boil): See cutaneous leishmaniasis above or full discussion of leishmaniasis.
Trypanosomiasis (American): See Chagas' disease summary or full discussion.
Trypanosomiasis (African) or African sleeping sickness (Tropical Africa): Trypanosomiasis is caused by protozoal parasites, Trypanosoma brucei rhodesiene or T b gambiense, transmitted by bite of the tsetse fly. T b rhodesiene infections are more virulent than T b gambiense; and in the former, patients experience three stages of illness (trypanosomal chancre, hemolymphatic, and meningoencephalitic) as opposed to two stages in the latter (trypanosomal chancre and meningoencephalitic) with significantly milder symptoms. The painful trypanosomal chancre (3-10 cm) appears about two days after the bite and lasts 2-4 weeks. The hemolymphatic stage is characterized by high fevers lasting several days, with symptom-free periods of days to weeks. Less common manifestations of this stage are severe headache, malaise, arthralgia, lymphadenopathy, circinate rash, pruritis, and hepatosplenomegaly. Weight loss and debilitation also occur, and myocarditis may develop. The meningoencephalitic stage is characterized by progressive apathy, nighttime insomnia and daytime somnolence, anorexia, retarded speech, extrapyramidal signs (tremors, fasciculations, choreiform movements, and Parkinsonian-like appearance), and finally, coma and death. Treatment is complex and toxic, and depends on the infecting organism and stage of illness. Among the medications currently in use are suramin, melarsoprol, pentamidine, eflornithine, and corticosteroids.
Tuberculosis (Worldwide): Tuberculosis (TB) is a chronic infection - most commonly pulmonary - caused by the acid-fast bacillus, Mycobacterium tuberculosis. Infection is usually acquired through inhalation of infected droplets expelled by cough from a person with active disease. Most cases (85%) of TB are pulmonary. Pulmonary symptoms include cough, chest pain, and hemoptysis. Constitutional symptoms are often present in pulmonary disease, and include fever, chills, night sweats, fatigue, decreased appetite, and weight loss. Symptoms of extrapulmonary TB depend on the site(s) of infection. Tuberculosis should always be ruled out in any person at-risk or with the above symptoms. Medical evaluation includes complete medical and family/close contacts/travel history, physical examination, Mantoux tuberculin skin test, chest x-ray, and appropriate bacteriologic or histologic examinations, e.g., smear and culture of sputum. Treatment is according to (1) classification of disease, e.g., exposure without infection, infection without disease, current TB disease, previous TB disease, or TB suspected; (2) whether disease is drug-resistant; (3) immune status of the patient; and (4) other factors. The treatment of TB is complex and is evolving at a rapid pace. Readers are referred to the U.S. Centers for Disease Control and Prevention: http://www.cdc.gov/ for current standards of testing and treatment.
Tungiasis (tropical areas of Africa and the Americas): Tungiasis is infestation with Tunga penetrans (sand fleas, jiggers), usually of the foot. Other fleas also bite humans and can transmit a variety of diseases.
Typhomalarial fever: See Brucellosis.
Typhoid and paratyphoid fever (sometimes termed enteric fever) (Most of the developing world, especially Africa, Asia, and Latin America, including Mexico): Typhoid fever is an acute systemic febrile illness caused by Salmonella typhi and other anaerobic gram-negative Salmonella serovars, e.g., S. paratyphi, which causes the less severe paratyphoid fever. Typhoid is usually spread by feces-contaminated food or water. Note that vaccination is not completely effective. Incubation is highly variable, ranging from 3-60 days. The hallmark sign is the gradual onset of steadily increasing and then persistently high fever (though children may experience abrupt onset). Early manifestations are fever, chills, malaise, headache, sore throat, cough, and sometimes abdominal pain and constipation or diarrhea. As the illness progresses, prostration, abdominal distension, hepatosplenomegaly, anorexia, and weight loss are common. Untreated typhoid may result in complications in any of the body systems. The severity of illness varies according to immunocompetence, infectious dose of microorganisms, and other factors. Treatment is with chloramphenicol 3-4 g/d po for adults and 50-75 mg/kg/d po for children. When the patient becomes afebrile, the dose may be decreased to 2 g/d for adults and 30 mg/kg/d for children. The total duration of treatment is two weeks. In the U.S., the more common treatment is amoxicillin 4-6 g/d po in four divided (1-1.5 g) daily doses for adults and 100 mg/kg po in four divided daily doses for children. Trimethoprim-sulfamethoxazole, ciprofloxacin, or ofloxacin are also used. Early effective treatment results in increased frequency of (usually mild) relapse.
Typhus: See full discussion (numerous areas of the world as noted in discussion below): The typhus group of illnesses are one of several rickettsioses or febrile exanthematous illnesses caused by bites of rickettsial-infected arthropods or exposure to their feces. The three most important typhus group diseases are: epidemic louse-borne typhus, scrub typhus, and endemic (murine) typhus. (1) Epidemic louse-borne typhus is caused by Rickettsia prowazekii, with infection favored by crowded, unsanitary living conditions such as in concentration or the more primitive refugee camps - especially those in cold areas. Epidemic louse-borne typhus is currently most prevalent in mountainous areas of Africa, Asia, and Latin America. It is characterized by a prodrome of headache and constitutional symptoms; then the abrupt onset of high fever, chills, and prostration; then a macular rash progressing to maculopapular and petechial. Other common manifestations are delirium, conjunctival injection, photophobia, eye pain, flushed facies, hearing loss, hypotension, pulmonary involvement, renal insufficiency, and splenomegaly. Recovery may be spontaneous, or complications, including pneumonia, circulatory collapse, myocarditis, and uremia may lead to death. Treatment is with doxycycline 200 mg in a single dose or until the patient is afebrile for 24 hours. (2) Scrub typhus is transmitted by the bite of infected mites or chiggers, and is found in most areas of Asia. Scrub typhus illness ranges from mild to severe, and is characterized by gradual onset of fever, chills, headache, myalgia (backache), cough, nausea and abdominal pain, eschar at the site of the infecting bite, regional lymphadenopathy and a maculopapular rash. Severe scrub typhus is characterized by encephalitis and pneumonia. Scrub typhus is treated with doxycycline 100 mg bid po for 7-14 days; or chloramphenicol 500 mg qid po for 7-14 days. Azithromycin is also effective. (3) Endemic (murine) typhus is transmitted by the bite of infected fleas and is found worldwide. Endemic typhus is characterized by several days of prodromal constitutional symptoms, followed by the abrupt onset of fever, chills, and nausea and vomiting. Pulmonary involvement is common and may include interstitial pneumonia, pleural effusion, and/or pulmonary edema. Treatment is with doxycycline 100 mg bid po for 7-14 days; or chloramphenicol 500 mg qid po for 7-14 days.
Vibrio parahaemolyticus and other vibrio species (worldwide): Vibrio are motile, anaerobic, curved, gram-negative rods that cause (according to species) gastrointestinal (notably cholera) and septic illnesses; and wound, skin, and opthalmic infections. In the U.S., Vibrio parahaemolyticus is transmitted by ingestion of undercooked seafood. In the U.S., infection results in abdominal pain, nausea, vomiting, and watery diarrhea; while in South Asia, infection causes more serious dysentery, but is seldom life-threatening. Treatment is supportive.
Visceral leishmaniasis (kala-azar): See full discussion (East and North Africa, Middle East, Southern Europe, Central, South, and East Asia, South America, West Mexico): Cardinal signs of visceral leishmaniasis are prolonged fever, splenomegaly, anemia, leukopenia, or hypergammaglobulinemia. A cutaneous nodule may or may not appear at the site of the bite. Systemic symptoms include gradual onset fever that often rises and falls twice/day, fatigue, weight loss, dizziness, cough, and diarrhea. Visceral manifestations include pronounced splenomegaly (hard, non-tender) and to a lesser extent hepatomegaly. Other manifestations may include generalized lymphadenopathy; hyperpigmented skin of the forehead, abdomen, hands, and feet in light-skinned persons; skin lesions in dark-skinned persons; signs of bleeding (petechiae, epistaxis, bleeding gums); jaundice and ascites; and progressive wasting. Onset may also be acute, with the above manifestations appearing a few weeks after infection. Treatment has traditionally been unsatisfactory because of drug toxicities, poor responses, multiple disease syndromes, and other factors - including recently, the emergence of antimony-resistant strains. Orally administered miltefosine has recently shown great promise. Other treatments include intravenous sodium stibogluconate (a pentavalent antimony compound) for 10-60 days depending on where the disease was contracted and whether illness is first or second episode.
Weil's syndrome: See leptospirosis.
Yaws (frambesia) (tropical areas worldwide): Yaws is a chronic childhood illness caused by Treponoma pallidum ssp. pertenue (see other treponematoses) spread primarily by skin to skin contact. Yaws is characterized by an initial papule, which enlarges and becomes papillomatous. The lesion erodes and infectious crusting exudate appears, as well as lymphadenopathy. The initial or "mother" lesion heals, but before or after healing of the initial lesion, secondary lesions appear in a variety of forms. Late or chronic yaws appear in about 10% of patients five or more years after the initial infection. Late yaws is characterized gummatous (granulomatous) lesions of the skin and subcutaneous tissues. The bones are also affected and eventually there is erosion of the nose and facial bones. The preferred treatment is 2.4 million units of IM benzathine penicillin G for adults and 1.2 million units for children.
Yellow fever (most of tropical and subtropical South America and Africa): Yellow fever (YF) is caused by an arbovirus transmitted by the Aedes aegypti mosquito from one human to another (the urban form of YF) or from monkeys to humans (the jungle or sylvan form of YF). YF is characterized by sudden onset flu-like (non-specific) symptoms occurring in two stages with a short intervening remission. The first stage of severe YF has a sudden onset of fever, chills, intense headache, lumbosacral back pain, myalgia, nausea and vomiting, conjunctival injection, dark urine, and bradycardia in relation to fever. After a 12-24 hour remission, there is an "intoxication" or hepatorenal stage that features reemergence of generalized symptoms including increased temperature, increased nausea and vomiting, abdominal pain, jaundice, and prostration. Complications of severe YF include jaundice, dehydration, decreased renal function, delirium, and hemorrhagic symptoms. Terminal signs include progressive tachycardia, intractable hiccups, and shock. Lab findings include albuminuria, leukopenia, abnormal liver function, increased prothrombin times. Treatment is supportive, i.e, control of fever, vomiting, dehydration, and pain.
References (Also see references in specific disease files)
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