American Trypanosomiasis (Chagas' Disease)

Description

Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi. Chagas' disease is usually transmitted by contact with the feces of an infected triatomine ("cone nose" or "kissing") bug. Transmission can also occur through blood transfusion and organ transplantation and congenitally through passage of parasites across the placenta.

Occurrence

Chagas' disease occurs in Mexico, Central America, and South America; acquisition of infection in the United States is rare. An estimated 11 million people are infected worldwide; of these, 15%-30% have clinical symptoms.

Risk for Travellers

Travellers rarely acquire Chagas' disease. Triatomine bugs typically infest poor-quality buildings constructed of mud, adobe brick, or palm thatch, particularly those with cracks or crevices in the walls and roof. Because the bugs primarily feed at night, travellers can greatly reduce their risk for acquiring infection by avoiding overnight stays in such dwellings and by not camping or sleeping outdoors in endemic areas. Travellers should be aware that blood products might not be routinely or adequately tested for T. cruzi prior to transfusion.

Clinical Presentation

Acute infection is usually asymptomatic but may be accompanied by local swelling at the site of inoculation, fever, and in 5%-10% of cases, meningoencephalitis, myocarditis or both. An asymptomatic phase follows the acute infection and lasts for life in 70%-80% of cases. Cardiomyopathy and/or intestinal "mega" syndromes (e.g., megaoesophagus and megacolon) develop in the rest of infected persons 10-40 years after infection.

Prevention

No vaccine is available. Preventive measures include insecticide spraying of infested houses. Insecticide-impregnated bed nets may reduce the risk of infection for travellers who cannot avoid camping or sleeping outdoors or in poorly constructed houses in endemic areas.

Treatment

Treatment is recommended for all cases of acute infection, congenital infection, and reactivated infection in immunocompromised patients. Treatment of chronically infected persons (especially children) may eliminate parasites in up to 60% of cases. The drugs of choice are nifurtimox (under an investigational New Drug Protocol from the CDC Drug Service) or benznidazole (not available in the United States). Travellers should be advised to consult an infectious disease or tropical medicine specialist. Persons with chronic cardiac or gastrointestinal disease may benefit from symptomatic therapy.

Bibliography
  • Barrett MP, Burchmore RJS, Stich A, et al. The trypanosomiases. Lancet. 2003;362:1469-80.
  • Dias JCP, Silveira AC, Schofield CJ. The impact of Chagas' disease control in Latin America: a review. Mem Inst Oswaldo Cruz. 2002;97:603-12.
  • Miles, M. American trypanosomiasis (Chagas' disease). In: Cook GC, Zumla A, editors. Manson's tropical disease. 21st ed. London: Elsevier Science; 2003. p. 1325-37.
  • Miles MA, Feliciangeli MD, de Arias AR. American trypanosomiasis (Chagas' disease) and the role of molecular epidemiology in guiding control strategies. BMJ. 2003;326:1444-8.
  • Prata A. Clinical and epidemiological aspects of Chagas' disease. Lancet Infect Dis. 2001;1:92-100.
  • Tyler KM, Miles MA, editors. World class parasites. Volume 7: American trypanosomiasis. Boston: Kluwer Academics; 2003.
  • WHO Expert Committee. Control of Chagas' disease. World Health Organ Tech Rep Ser. 2002;905:1-109.

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