2 YEARS INVESTIGATION OF EPIDEMIC HEPATITIS-E VIRUS TRANSMISSION IN WEST KALIMANTAN (BORNEO), INDONESIA

Two years' follow-up investigation of a hepatitis E virus (HEV) outbre ak in West Kalimantan, Indonesia in 1991 was carried out to investigat e the epidemiology of epidemic HEV transmission and the persistence of the immunoglobulin G (IgG) antibody response. Sixty cases identified as anti-HEV IgG positive during the outbreak in 1991 were matched with 67 controls and examined, together with 318 members of their families . Overall, the prevalence of anti-HEV IgG among the 445 subjects (repr esenting 127 households) was 59%. There was no significant difference in anti-HEV prevalence between cases (72%) and controls (61%). Loss of detectable anti-HEV IgG after 2 years was demonstrated in 17 of 60 su bjects (28%) who were originally positive for anti-HEV in 1991. The me an number of anti-HEV positive subjects per household was 2.04. Cross- sectional prevalence of anti-HEV IgG increased significantly with age (P=0.01). When communities were grouped into areas of low (<40%), medi um (40-59%) and high (greater than or equal to 60%) anti-HEV prevalenc e, use of river water for drinking and cooking (P<0.001), personal was hing (P<0.0001), and human excreta disposal (P<0.001) were associated with high prevalence communities. Conversely, boiling drinking water w as negatively associated with increased prevalence(P=0.02). Subnormal rainfall during the month (August) leading up to the 1991 outbreak (19 cm compared to the monthly mean of 209 cm in 1985-1993) may have cont ributed to favourable epidemic conditions.