First report of hepatitis E virus viremia in healthy blood donors from Nepal

Abstract

The aim of this study was to detect the prevalence of hepatitis E virus (HEV) in healthy blood donors so as to decipher the maintenance of (HEV) reservoir if any. Five hundred and eighty-one blood samples along with clinical information were collected from central blood bank, Kathmandu between February and March 2014. Samples were tested for hepatitis B virus surface antigen, anti-hepatitis C virus antibodies, anti-hepatitis A virus IgM, HEV antigen, HEV viral load and anti-HEV antibodies (IgM and IgG) by ELISA. Only those samples positive with anti-HEV IgM were tested for HEV RNA by reverse transcriptase nested PCR. Age adjusted prevalence of IgM anti HEV and IgG anti HEV were 3.6 and 8.3 % respectively. No significant difference in Median ALT levels was noted between HEV RNA positive and negative subjects. Sequence analysis of HEV shows all genotype belongs to genotype 1a. Phylogenetic analysis shows the virus has homology of 95 % with strain from India and Nepal outbreak of April 2014. This study sheds light on how inter epidemic reservoirs can be maintained in healthy population with asymptomatic cases. This raises an important question regarding nature of HEV as well as its tendency to circulate in blind sight and also cause periodic outbreaks in endemic setting like Kathmandu.Keywords HEV Á Nepal Á Blood donors Hepatitis E virus (HEV) infection is endemic in Kathmandu Valley the capital of Nepal. Four epidemics have been documented so far during 1973, 1981-1982, 1987 and 2005-2006 and variable numbers of sporadic acute hepatitis E occurred in between [4]. There have been decline in number of acute hepatitis E cases in recent years and hepatitis A infection has outnumbered HEV as an etiology of acute hepatitis in adults [3]. What maintains the virus in the population during low incidence period of acute hepatitis is a matter of debate. There are some evidences that rodents may serve as animal reservoirs for HEV [2].Occurrence of HEV viremia in healthy blood donors has been increasingly reported across the globe mainly from Europe [5], and China [1] where genotype 3 and 4 predominate. To explore the possibility of HEV viremia in healthy blood donors of Nepal, we collected blood samples along with demographic data from 581 healthy voluntary blood donors from central blood bank, Kathmandu, Nepal during February-March 2014. Study subjects constituted 401 men and 180 women volunteer blood donors. Median age of the subjects was 35 years (range 18-55). Elevated ALT levels ([40 IU/L) were noted in 81(13.9 %) with median ALT value of 23 IU/l (range 5-98 IU/L). IgG anti-HEV was detected in 56 samples (9.5 %) and IgM anti-HEV was detected in 27 samples 4.6 %). When adjusted for the age the prevalence of IgM anti HEV and IgG anti HEV were 3.6 and 8.3 % respectively. No significant difference in Median ALT levels was noted between HEV

Hepatitis E virus seroprevalence among blood donors in Pune, India

“…Similarly, Zhang et al have reported that the majority of HEV infections in RNA‐positive donors in China were attributed to genotype 1 (19/33 = 58%) and genotype 4 (14/33 = 42%). In a similar line, Gupta et al had reported hepatitis E viremia in healthy blood donors in Nepal for the first time in 2016, where seven of 27 anti‐HEV IgM‐positive donors were found HEV RNA positive belonging to genotype 1.…”

“…The seroprevalence rates in many European countries ranging from 1.3% to 52% have been reported. Similarly, seroprevalences of HEV in blood donors ranging from 1.8% to 9.8% in South America, 3.4% to 30% in several Asian countries have been reported. The current study from India, a developing country, showing a prevalence rate of 17.70% goes at par with rates reported in several Asian countries attributing to similar endemicity of HEV infection.…”

Prevalence of hepatitis E viraemia among blood donors: a systematic review

“…On review of full‐text articles for the remaining 140 citations, 83 did not meet selection criteria. Of the 57 citations selected for final data synthesis , one provided three data sets ; hence, we had a total of 59 data sets from 28 countries (Fig. ).…”

“…A large majority of data sets were from Europe, high or high‐middle income countries in Asia and North America (27, 12 and 4 data sets, respectively); by comparison, there were only eight studies from low/low‐middle income countries of Asia and Africa; the remaining eight data sets were from other parts of the world. In 39 data sets, all the blood units had been tested for HEV RNA, whereas in 20 data sets, the blood units were first screened for the presence of anti‐HEV antibodies ( n = 17) or for elevated serum ALT levels ( n = 3) , with only the screen‐positive units being tested for HEV RNA.…”

Post-Earth Quake assessment of HEV prevalence among general population

“…Interestingly, the case fatality rate is very high projecting 16-38% among pregnant women as a result of, unexplainably high rate of fulminant hepatic failure, in comparison to general population curtailing to 1-3% [7]. The increasing reports of HEV being transmitted through blood transfusion also highlights the potential risk, this virus poses to blood supply safety [13,14]. However, screening for acute HEV infection serologically or HEV RNA is not routinely performed in Nepalese hospitals for any clinical procedures-blood transfusion or surgery.…”