The epidemiology of hepatitis A in Rio de Janeiro: environmental and domestic risk factors

Abstract

SUMMARYA serological study of hepatitis A was carried out in low-income areas scheduled for a major sanitation programme in Rio de Janeiro, Brazil. Blood spots were collected by finger puncture and transported on filter paper, and total antibodies to hepatitis A virus were detected by ELISA. Households were also interviewed to collect information on their environmental conditions and socio-economic status. A generalized linear model using a complementary log-log function was fitted to the data, using the logarithm of age as an explanatory variable to derive adjusted rate ratios (RR). The risk of infection was greater among households with 2-3 members per room (RR l 1n4 ; 95 % CI l 1n04-1n8) or more than three per room (RR l 1n5 ; 95 % CI l 1n2-2n0). People living on hilltops (RR l 1n5 ; 95 % CI l 1n02-2n2), near to open sewers (RR l 1n2 ; 95 % CI l 1n03-1n5) or lacking a kitchen (RR l 1n4 ; 95 % CI l 1n08-1n9) were also at greater risk than others. The number of taps and water-using fittings in the house was associated with a protective effect (RR l 0n9 for each tap ; 95 % CI l 0n9-0n98). A significant protective association was found with maternal education but not with gender or household income. The results do not suggest a strong association with water quality. Ownership of a ceramic water filter was associated with a protective effect on the margin of significance, but the practice of boiling drinking-water was not, nor was the type of water source used. The results suggest that that the risk of infection with hepatitis A is determined by environmental variables in the domestic and public domains.

Prevalence of anti-hepatits A antibodies in children of different socioeconomic conditions in Vila Velha, ES

“…The correlation between positive anti-HAV serology and various factors including age, low socioeconomic status, absence of sewage facilities, domestic water filter and a past history of hepatitis in the family supports similar findings elsewhere in the world 5 18 19 as well as in Brazil 3 . As reported in Chile 9 , swimming in the sea or a river, was not positively associated with the presence of anti-HAV antibodies.…”

Risk factors for infection with Giardia duodenalis in pre-school children in the city of Salvador, Brazil

“…The presence of an open sewer near the house has been found to be associated with infection of Brazilian children with other faecal pathogens [25,26]. Exposure to open sewers can be seen as analogous to exposure to untreated wastewater used for irrigation [27] although, in the latter, the associated risk seems to stem from the consumption of the irrigated vegetables rather than from wastewater contact [28].…”

Seroprevalence of hepatitis A in children and adolescents

“…Sabe-se que o grau de instrução também é relacionado à renda da família, sendo que esses fatores se sobrepõem. Em um estudo nacional, as crianças cujas mães apresentavam entre 0 e 3 anos de estudo apresentaram uma prevalência de 32,55%, comparados com 13,57% de positividade nas crianças cujas mães tinham mais de 11 anos de estudo 26 . Em nossa casuística, também se observou uma associação positiva entre a menor escolaridade materna e a presença de anticorpos, além disso, observou-se a mesma associação com a escolaridade paterna.…”

“…Esse fato também foi observado no presente estudo na análise univariada, mas não permaneceu na análise multivariada 26 .…”