Chagas disease in an area of recent occupation in Cochabamba, Bolivia

Introduction A descriptive,entomological and seroepidemiological study on C hagas disease was conducted in a place of recent occupation on the outskirt s of Cochabamba, Bolivia: Avaroa/Primer de Mayo (population: 3,000), where the socio-economic level is low and no control measures have been made avai lable. Methods The immunofluorescent antibody test (IFAT) was used for IgG and IgM anti-Trypanosoma cruzi antibodies in tilter paper bloodspot eluates from 1 28 subjects (73 females, 55 males) selected by systematic sampling. Concern ing each subject age, gender, birthplace, occupation, duration of residence and building materials used in their houses were recorded. Vectors were ca ptured both in domestic and peridomestic environments. Results Seropositive, 12.5% (16/128): females, 15.1% (11/73); males, 9.1% ( 5/55). Average time of residence: 6.1 years for the whole population sample and 7.4 years for the seropositive subjects. Most houses had adobe walls ( 76.7%, n = 30), galvanized iron rooves (86.7%) and earthen floors (53.4%) 8 0% of the walls had crevices. One hundred forty seven specimens of Triatoma infestans were captured, of which 104 (70.7%) were domestic, and I peridom estic Triatoma sordida. Precipitin host identification: birds, 67.5%; human s, 27.8%; rodents, 11.9%; dogs, 8.7%; cats, 1.6%. House infestation and den sity indices were 53.3 and 493.0 respectively. We found 21 (14.3%) specimen s of T: infestans infected with trypanosomes, 18 (85.7%) of which in domest ic environments. Discussion The elements for the vector transmission of Chagas disease are p resent in Avaroa/Primer de Mayo and the ancient custom of keeping guinea pi gs indoors adds to the risk of human infection. In neighboring Cochabamba, due to sub-standard quality control, contaminated blood transfusions are no t infrequent, which further aggravates the spread of Chagas disease. Prompt action to check the transmission of this infection, involving additionally the congenital and transfusional modes of acquisition, is required.