(P-TS-2) A Pilot Study of Prevalence of Hepatitis E in Blood Products in the Midwest

Hepatitis E virus (HEV) is a single-stranded RNA virus that can cause acute hepatitis in humans and develop into chronic liver disease with or without extrahepatic manifestations, especially in immunocompromised individuals who often receive blood prodcuts. HEV has historically been associated with fecal-oral transmission in developing countries. Recent studies have indicated that the prevalence of HEV has been underestimated in developed countries due to asymptomatic infections and insensitive testing methods^1,2. Notably, genotypes HEV3 and HEV4 are now understood to be zoonotically transmitted to humans, commonly from pigs and boars. Several studies have indicated an increased prevalence of HEV in regions such as the Midwestern United States, presumably due to increased swine population, as evidenced by higher seropositivity for anti-HEV IgG antibody,³ several instances of HEV RNA-positive blood donors, and a frequency of HEV IgM of 0.58% in this region⁴.

Currently, blood products are routinely tested for human immunodeficiency virus 1 and 2, hepatitis B virus, hepatitis C virus, human T-lymphotropic virus types 1 and 2, Treponema pallidum, West Nile virus, and Trypanosoma cruzi, with additional testing for cytomegalovirus, Babesia, and Zika virus in special circumstances. There is no routine testing for HEV in donated blood products, and no FDA-approved test exists for diagnosis of HEV⁵. Given the frequency of HEV IgM and positive HEV RNA in blood donors in the Midwest, we sought to assess the prevalence of HEV RNA in our blood supply which is mostly locally sourced.

Study

Design/Methods:

At a Midwest academic center, integrally attached samples of blood products were used for this study over a two-year period. RNA was extracted from the segments using Qiagen viral RNA extraction kits and an automated extraction system. A real-time reverse transcription-polymerase chain reaction assay was developed, validated utilizing the World Health Organization International HEV reference standards covering genotypes 1 through 4, and performed in duplicate on the blood product sample RNA extracts for detection of HEV. An MS2 bacteriophage (a single-stranded RNA virus) was used as the positive control for extraction and nucleic acid amplification. 

Results/Findings:

In total, 1,495 platelet samples and 2,418 red blood cell samples were assayed for HEV RNA. Of the 3,913 blood products tested, no samples resulted as positive for HEV RNA. The positive control was detected in all tests.

Conclusions: Though prior studies have indicated an frequency of 0.58% HEV IgM seropositivity in the Midwest⁴, the absence of HEV in the 3,913 blood products over two years of testing tested indicates a prevalence of HEV RNA in the blood supply from this region as being lower.