Seroincidence of intrapartum hepatitis e virus infections declines in pregnant Bangladeshi women between 2001 and 2010

Abstract

HepatitisEvirus (HEV) is the leading cause of acute viral hepatitis globally and results in severe morbidity andmortality in pregnantwomen. There is a paucity of longitudinal data examining the incidence and disease rate ofHEVin cohorts of pregnancy in endemic areas. We studied serial sera collected within two prospective cohorts totaling 110,473 incident pregnancies enrolled large randomized trials in rural northwestern Bangladesh, between 2001 - 2007 (cohort A) and 2007 - 2010 (cohort B). An NIH research immunoassay was used to identify anti-HEV IgG status in early pregnancy, late pregnancy and 3 month postpartum venous blood specimens, drawn on a subsample of the larger cohorts. Of the 1,127 specimens available for testing in cohort A, 72 were anti- HEVseropositive at baseline, indicating a seroprevalenceof~6.4%.During this period, 63 women were identified as potential seroconverters, suggesting an incidence rate of ~56 infections per 1000 person-years. In the more recent cohort B, 1100 were available for testing, revealing a ~6.1% seroprevalence in anti-HEV IgG at early pregnancy.Within this cohort, 40 women were identified as putative seroconverters, an incidence rate of 46 infections per 1000 person-years. Between the 2001 to 2006 cohort and the 2008 to 2010 cohort, the incidence of intrapartum HEV infections seems to be declining in rural Bangladesh, possibly reflective of improved sanitation. In the cohort A, 4 pregnant seroconverters with high antibody titers were evaluated for cytokine profiles, revealing elevated levels of pro-inflammatory cytokines compared to unifected controls andwomen whowere seropositive at baseline.Cytokine analysis of the 2008 to 2010 cohort is ongoing to characterize the immunopathology of HEV infection. This data will elucidate population-based rates of HEV disease:infection ratioswithin a non-epidemic context, where this pathogen is ubiquitous.