Outbreak of hepatitis E in urban Bangladesh resulting in maternal and perinatal mortality

An outbreak of hepatitis E in an urban area of Bangladesh

We investigated an outbreak of jaundice in urban Bangladesh in 2010 to examine the cause and risk factors and assess the diagnostic utility of commercial assays. We classified municipal residents reporting jaundice during the preceding 4 weeks as probable hepatitis E cases and their neighbours without jaundice in the previous 6 months as probable controls. We tested the sera collected from probable cases and probable controls for IgM anti-hepatitis E virus (HEV), and the IgM-negative sera for IgG anti-HEV using a commercial assay locally. We retested the IgM-positive sera for both IgM and IgG anti-HEV using another assay at the Centre for Disease Control and Prevention (CDC), USA. Probable cases positive for IgM anti-HEV were confirmed cases; probable controls negative for both IgM and IgG anti-HEV were confirmed controls. We explored the local water supply and sanitation infrastructure and tested for bacterial concentration of water samples. Probable cases were more likely than probable controls to drink tap water (adjusted odds ratio: 3.4; 95% CI: 1.2-9.2). Fifty-eight percentage (36/62) of the case sera were IgM anti-HEV positive; and 75% of the IgM-positive samples were confirmed positive on retesting with another assay at CDC. Compared to confirmed controls, cases confirmed using either or both assays also identified drinking tap water as the risk factor. Two tap water samples had detectable thermotolerant coliforms. Research exploring decentralized water treatment technologies for sustainable safe water might prevent HEV transmission in resource-poor cities. Detection of serological markers in a majority of probable cases implied that available diagnostic assays could adequately identify HEV infection during outbreaks.

Arsenic exposure and hepatitis E virus infection during pregnancy

BACKGROUND

Arsenic has immunomodulatory properties and may have the potential to alter susceptibility to infection in humans.

OBJECTIVES

We aimed to assess the relation of arsenic exposure during pregnancy with immune function and hepatitis E virus (HEV) infection, defined as seroconversion during pregnancy and postpartum.

METHODS

We assessed IgG seroconversion to HEV between 1st and 3rd trimester (TM) and 3 months postpartum (PP) among 1100 pregnancies in a multiple micronutrient supplementation trial in rural Bangladesh. Forty women seroconverted to HEV and were matched with 40 non-seroconverting women (controls) by age, parity and intervention. We assessed urinary inorganic arsenic plus methylated species (∑As) (µg/L) at 1st and 3rd TM and plasma cytokines (pg/mL) at 1st and 3rd TM and 3 months PP.

RESULTS

HEV seroconverters' urinary ∑As was elevated throughout pregnancy. Non-seroconverters' urinary ∑As was similar to HEV seroconverters at 1st TM but declined at 3rd TM. The adjusted odds ratio (95% confidence interval) of HEV seroconversion was 2.17 (1.07, 4.39) per interquartile range (IQR) increase in average-pregnancy urinary ∑As. Increased urinary ∑As was associated with increased concentrations of IL-2 during the 1st and 3rd TM and 3 months PP among HEV seroconverters but not non-seroconverters.

CONCLUSIONS

The relation of urinary arsenic during pregnancy with incident HEV seroconversion and with IL-2 levels among HEV-seroconverting pregnant women suggests arsenic exposure during pregnancy may enhance susceptibility to HEV infection.

Experimental infection of pregnant rabbits with hepatitis E virus demonstrating high mortality and vertical transmission

A high mortality rate of approximately 20% in pregnant women with hepatitis E has been reported in previous studies. However, other studies showed no difference between pregnant and nonpregnant women in the severity of hepatitis E. To determine the effects of HEV infection on pregnancy, we successfully established HEV infection in six pregnant rabbits (PR) and six nonpregnant rabbits (NPR) with a rabbit HEV isolate, taking three PR and one NPR without HEV infection as controls. Tests for HEV RNA by RT-PCR, anti-HEV antibodies by ELISA and HEV antigen via immunohistochemistry and histopathology were carried out. Two of six infected PR miscarried and three of the remaining four PR died which may be attributed to severe liver necrosis caused by HEV infection. Moreover, vertical transmission was found to be associated with the replication of HEV in placenta, indicated by the presence of HEV RNA and antigen in placenta from the infected PR. Our findings strongly suggest that HEV infection could lead to adverse outcomes in pregnancy and vertical transmission, suggesting the necessity for pregnant women at risk of HEV infection to be vaccinated.