A associação entre a hepatite B e a esquistossomose mansônica: uma falácia ecológica

Chronic carriers of hepatitis B surface antigen in an endemic area for schistosomiasis mansoni in Brazil

“…Moreover, the populations studied did not present the usual risks for hepatitis B described for urban areas (parenteral treatment, dental manipulations, tattoing) and transmission of hepatitis was probably from mother-tochild, child-to-child and by sexual intercourse (Leichtner et al 1981, Coltorti et al 1984, Franks et al 1989, Hurie et al 1992. Other markers for sexually transmitted diseases such as FTA-abs (performed in randomly selected sera of 250 individuals of each area) resulted negative (Serufo 1997).…”

“…The problems included miscalculation of sample sizes in the majority, the absence of control groups or the inadequate selection of groups and/or major losses of patients during follow up in some, and the low accuracy of old laboratory tests used to diagnose hepatitis B in studies made in the seventies (Serufo & Lambertucci 1997, Serufo 1997. This is the first field-based study on the association of hepatitis B and schistosomiasis in Brazil in which the index of chronicity for hepatitis B was compared in endemic and nonendemic areas.…”

Schistosomiasis and associated infections

“…Summing-up, in hospital-based studies the carrier rate of HBV in patients with hepatosplenic schistosomiasis was higher than in the controls, whilst in field-based studies an association between these organisms has not been found (Serufo 1997). Further observations with well-designed studies are necessary to clarify this controversy.…”