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Chapter 4

CHAGAS' DISEASE (AMERICAN TRYPANOSOMIASIS)

With Luiz Felippe Mattoso

There are few diseases confined to one continent. Fortunately for the rest of the world, Chagas' disease occurs only in the central and southern half of the Western hemisphere, from Texas to Patagonia. Restricted though it is, there are 90 million people at risk of infection and 18 million infected individuals according to the 1998 World Health Report issued by the WHO. It is thus one of the most important public health problems in many South American nations. In Brazil 20% of the population in the endemic areas are infected. Once a disease of the rural poor, the increased migration of rural workers to the cities has made it an urban disease as well. Sao Paulo, with over 350,000 infected persons, accounts for most of the new cases seen in Brazil each year. A recent national study revealed that there are between 5 and 6 million people with Chagas' disease in that country and that 30% of all adults with clinical evidence of chronic Chagas' disease die as a result of their infection.

Chagas' disease presents with many different manifestations in both its acute and chronic stages. In the acute phase it may cause acute diffuse myocarditis and encephalitis; in the chronic form, in addition to serious myocardiopathy, there is a decrease in the number of ganglion cells in the central and peripheral autonomic nervous system. This may lead to marked enlargement of the heart, esophagus, colon and other hollow viscera. The heart is the organ most commonly involved and, in both the acute and chronic phases, myocarditis accounts for greater morbidity and mortality than does involvement of all other organs. Despite research since 1909, when it was first described by Carlos Chagas, it remains a puzzling and incurable disease with many unresolved problems. Campaigns against the disease have often been half-hearted since it affects mostly the poor, although the spraying of insecticides to kill the reduviid bug vectors and the increased testing of blood to eliminate transmission by infected blood transfusions offer some hope for partial control.

Synonyms

Chagas' disease/syndrome. American trypanosomiasis. Chagas-Cruz disease. Barbeiro fever. Careotrypanosis. Opilation. Sp: Enfermedad de Chagas. Opilacao. Schizotripanosomiasis. Tripanosomiasis. Fr: Trypanosomose de Cruz. Maladie de Chagas. Schizotrypanose. Ger: Chagas-Krankheit. Chagassche Krankheit. Amerikanische Schlafkrankheit.

Definition

Chagas' disease is an acute, subacute, or chronic infection by Trypanosoma cruzi, a flagellated protozoan that circulates in the blood of man and other hosts.

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