Hepatitis E virus seroepidemiology: a post-earthquake study among blood donors in Nepal.

Ashish C. Shrestha,Veronica C. Hoad,Manita Rajkarnikar,Shrawan K. Shrestha,Helen M. Faddy,Clive R. Seed,Robert L. P. Flower,Uru Thapa

doi:10.1186/s12879-016-2043-8

Abstract

BackgroundAs one of the causative agents of viral hepatitis, hepatitis E virus (HEV) has gained public health attention globally. HEV epidemics occur in developing countries, associated with faecal contamination of water and poor sanitation. In industrialised nations, HEV infections are associated with travel to countries endemic for HEV, however, autochthonous infections, mainly through zoonotic transmission, are increasingly being reported. HEV can also be transmitted by blood transfusion. Nepal has experienced a number of HEV outbreaks, and recent earthquakes resulted in predictions raising the risk of an HEV outbreak to very high. This study aimed to measure HEV exposure in Nepalese blood donors after large earthquakes.MethodsSamples (n = 1,845) were collected from blood donors from Kathmandu, Chitwan, Bhaktapur and Kavre. Demographic details, including age and sex along with possible risk factors associated with HEV exposure were collected via a study-specific questionnaire. Samples were tested for HEV IgM, IgG and antigen. The proportion of donors positive for HEV IgM or IgG was calculated overall, and for each of the variables studied. Chi square and regression analyses were performed to identify factors associated with HEV exposure.ResultsOf the donors residing in earthquake affected regions (Kathmandu, Bhaktapur and Kavre), 3.2% (54/1,686; 95% CI 2.7–4.0%) were HEV IgM positive and two donors were positive for HEV antigen. Overall, 41.9% (773/1,845; 95% CI 39.7–44.2%) of donors were HEV IgG positive, with regional variation observed. Higher HEV IgG and IgM prevalence was observed in donors who reported eating pork, likely an indicator of zoonotic transmission. Previous exposure to HEV in Nepalese blood donors is relatively high.ConclusionDetection of recent markers of HEV infection in healthy donors suggests recent asymptomatic HEV infection and therefore transfusion-transmission in vulnerable patients is a risk in Nepal. Surprisingly, this study did not provide evidence of a large HEV outbreak following the devastating earthquakes in 2015.

Highlights

As one of the causative agents of viral hepatitis, hepatitis E virus (HEV) has gained public health attention globally
HEV Immunoglobulin M (IgM) prevalence was associated with a donor reporting having a history of jaundice or reporting pork consumption (p < 0.05) (Table 1)
Of the donors residing in earthquake affected regions (Kathmandu, Bhaktapur and Kavre), 3.2% of donors were HEV IgM positive, and two donors were positive for HEV antigen

Summary

Introduction

As one of the causative agents of viral hepatitis, hepatitis E virus (HEV) has gained public health attention globally. HEV epidemics occur in developing countries, associated with faecal contamination of water and poor sanitation. Hepatitis E virus (HEV) has gained public health attention as one of the causative agents of viral hepatitis. In Nepal, regular HEV outbreaks have occurred during the previous 4 decades, with reported outbreaks in 1973, 1981–1982, 1987, 1995 and 2014 [9,10,11]. Epidemics have been associated with faecal contamination of water, and molecular characterization has shown genotype 1 as a cause of acute HEV infection [18]. HEV antibodies and RNA have been detected in farm swine from Kathmandu [19], indicating the possibility of zoonotic transmission in addition to the usual faeco-oral route

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