The First Documented Detection of the Hepatitis E Virus in Rats in Taiwan

DOI: 10.6525/TEB.202201_38(2).0001

Pai-Shan Chiang, Wei-Lun Huang, Han-Hsuan Chung, Jyh-Yuan Yang, Hwa-Jen Teng*

2022 Vol.38 NO.2

Correspondence Author： Hwa-Jen Teng*

Abstract：

Hepatitis E virus (HEV) could be classified into four species (A, B, C and D). The host ranges of the four species are distinct. HEV-A infects humans and other mammals, including domestic pigs, goats and wild boars, deer, and camels. The other 3 species, HEV-B, HEV-C, and HEV-D, infect avian, rodent, and bat species, respectively. However, human infections by rat HEV (HEV species C/genotype 1, HEV-C1) have been reported recently, including a case who had visited Taiwan before having the illness in 2019. To investigate whether HEV-C1 is transmitting in rat population and causing human infections in Taiwan, 50 acute-phase human sera samples from HEV suspected patients with HEV-A negative results were re-tested for retrospective review of HEV-C. Besides, rat sera were collected from 3 Rattus tanezumi (previously known as Rattus rattus) and 47 R. norvegicus, which were captured at international airports or harbors. Identifying HEV-C RNA was performed by hemi-nested RT-PCR in human and rat serum samples. Rat sera were also tested for anti-rat HEV antibodies. HEV-C RNA was not detected in either human or R. tanezumi samples, but the viral RNA was identified in two R. norvegicus sera. Furthermore, the 2 rat HEV strains shared identical partial sequences in the RNA polymerases gene. In serology, anti-HEV antibodies were detected in 52% (26/50) of the trapped wild rats. This study documents the first detection of HEV-C1 in Taiwan. The seroprevalence and the high homology between HEV-C1 sequences from rats observed in this study might result from viral transmission 
within certain rodent populations. The risk for indigenous human infection in Taiwan should not be ignored because HEV-C1 with zoonotic potential has already been detected in the local rodent population.