Nested case-control study in a serological survey to evaluate the effectiveness of a Chagas disease control programme in Brazil.
OBJECTIVE
To identify risk factors associated with Trypanosoma cruzi infections in areas under surveillance in the State of Minas Gerais, Brazil.


METHODS
A model using a nested case-control design incorporated within a serological survey of schoolchildren which was employed to evaluate the effectiveness of the Chagas disease control programme.


RESULTS
In a sample of 40,374 schoolchildren (aged 7-14 years) surveyed, 16 children tested positive for T. cruzi antibody (by indirect immunofluorescence and indirect haemagglutination). In the case-control study, each case was randomly matched to three seronegative controls (classroom and age +/- 1 year). Compared to controls, T. cruzi-seropositive children were more likely to have a seropositive mother (odds ratio (OR) = 6.8; 95% confidence interval (CI) = 0.71-63.9) or a seropositive family member (OR = 8.6; 95% CI = 1.0-75.5).


CONCLUSIONS
Use of the nested case-control model in a sero-epidemiological survey to evaluate risk factors for T. cruzi transmission was adequate for assessing the effectiveness of a Chagas disease control programme.
Carneiro
M
M
Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Caixa Postal 486, 31270-901-Belo Horizonte, MG, Brazil. mcarneir@icb.ufmg.br
Moreno
E C
EC
Antunes
C M
CM
D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D014355:Chagas Disease / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D002648:Child; D003140:Communicable Disease Control; D005260:Female; D006801:Humans; D008297:Male; D011159:Population Surveillance; D015397:Program Evaluation / Q000379:methods*; D012307:Risk Factors