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. Treatment is focused on symptoms.
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.
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.
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.
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.
Leishmaniasis, visceral (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.
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.
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.
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.
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.
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).
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).
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.