SPECIFIC AND SENSITIVE IMMUNOLOGICAL DIAGNOSIS . OF CHAGAS' DISEASE BY COMPETITIVE ANTIBODY ENZYME MONOCLONAL ANTIBODY IMMUNOASSAY USING A TRYPANOSOMA CR UZI-SPECIFIC

Coexistence of Chagas' disease with leishmaniasis and T. rangeli infectionin endemic areas and cross-reactivity between corresponding etiological agents can confuse the immunodiagnosis of Chagas' disease. A discriminative serological test could therefore represent a major advance in specific immunodiagnosis. A competitive antibody enzyme immunoassay against a component 5-enriched preparation, using a T. cruzi species-specific monoclonal antibody has allowed development of a specific serodiagnosis of Chagas' disease with high sensitivity (96.6% in undetermined and chronic phases of infection). This test can differentiate Chagas' disease from other cross-reacting parasitic diseases in areas where concomitant infections are unknown or suspected. The parasitic protozoan Trypanosoma cruzi is the causative agent of Chagas' disease (American trypanosomiasis). At least 24 million people in Central and South America are estimated to be infected with T. cruzi. In the initial acute phase of Chagas' disease, lethal in about 10% of cases, trypanosomes can usually be detected in the circulating blood. In the undeterminate and chronic phases of infec- tion, parasitemia is very low and imniunosero- logical diagnosis is required. In vast areas of Central and South America, cutaneous, mucocutaneous2. or visceral leish- maniasis' and T. rangeli infection^^-^ are asso- ciated with T. cruzi infection. Due to a variable degree of cross-reactivity between the corre- sponding etiological agents8-I0 the precise diag- nosis of Chagas' disease using classical serolog- ical tests is not effective in areas where these diseases are coendemic. Attempts have been made to overcome such cross-reactivity using aniastigote or trypomas-