Hepatitis E virus in donor plasma collected in Japan

Area of Science:

• Virology
• Transfusion Medicine
• Epidemiology

Background:

• Human hepatitis E virus (HEV) is a global concern, with transfusion-transmitted cases recently identified.
• HEV RNA and seroprevalence have been studied regionally in Japan, with Hokkaido screening donor plasma.
• HEV RNA detection rates in Japanese blood donors outside Hokkaido remain unreported.

Purpose of the Study:

• To determine the HEV RNA detection rate in blood donors across Japan, excluding Hokkaido.
• To characterize HEV RNA positive samples, including viral load and genotype.
• To compare findings with previous studies in Hokkaido and Europe.

Main Methods:

• Tested 620,140 qualified donor plasma samples from 2004-2014 (excluding Hokkaido) for HEV RNA.
• Utilized pooled samples (n=50 or 500) for HEV RNA detection.
• Evaluated viral load, genotype, and anti-HEV IgG/IgM in positive samples.

Main Results:

• HEV RNA was detected at a rate of 1/15,075 donations (using pools of 50).
• Detection rates were higher in eastern than western Japan.
• All 36 HEV RNA-positive samples were genotype 3, with viral loads ranging from <1.69 to 7.22 log10 copies/ml.

Conclusions:

• The HEV RNA detection rate in Japanese donors outside Hokkaido is lower than in Europe and Hokkaido.
• All detected HEV strains were genotype 3, contrasting with genotype 4 reported in Hokkaido.
• Differences in detection rates may be influenced by varying RNA detection limits across studies.