ABSTRACT
A probabilistic model for intra-familial distribution of infectous disease is proposed and applied to the prevalence of positive serology for Trypanosoma cruzi infection in Northeastern Brazilian sample. This double with one tail excess model fits satisfactorily to the data and its interpretation says that around 51% of these 982 families are free of infection risk; among those that are at risk, 3% have a high risk (0.66), probably due to high domestic infestation of the vector bug; while 97% show a small risk (0.11), probably due to accidental, non-domestic transmission
Subject(s)
Chagas Disease , BrazilABSTRACT
A large bibliographic survey provided data on Trypanosoma cruzi serology covering the period l948-l984. Epidemiological-demographic methods provided an estimate of 11% for the prevalenceof positive serology in Brazil, by 1984. Significant temporal trends were observed for most of the Brazilian geographical regions as well as for Brazil, as a whole. The parabolic curve that fit best for the entire country, indicates that by 1991, the incidence of new positive serology would be close to zero. This conclusion needs further fine-adjustment, since the forecast point is somewhat distant from the measured period
Subject(s)
Humans , Chagas Disease/epidemiology , Brazil/epidemiology , Prevalence , Regression Analysis , Space-Time ClusteringABSTRACT
Com o objetivo de testar as discrepâncias observadas na segregaçäo dos grupos sanguineos ABO entre pares consecutivos de irmäos, como foi sugerido por Cifuentes and Valenzuela (1986) em uma populaçäo chilena, foram analisadas duas amostras brasileiras, cada uma com cerca de 1000 pares de irmäos. Os resultados mostram claramente a inexistência de diferenças significativas tanto nas amostras totais como nas subdividas de acordo com os fenótipos maternos, näo permitindo, portanto, a generalizaçäo dos resultados chilenos. As observaçöes agrupadas, das amostras brasileiras e a chilena näo apoiam a hipótese da existência de um mecanismo de "tolerância", postulada por Cirfuentes e Valenzuela. A necessidade de informaçöes completas de famílias nucleares é enfatizada, no sentido de evitar achados inconsistentes