Supporting data for Investigating Zoonotic Rat Hepatitis E Transmission from a One Health Perspective

To further assess the infectivity of rHEV and its host range, an immunocompromised rat model and two cell models, including primary rat hepatocytes and HepaRG, a human hepatocyte-like cell line, were used to compare the replication dynamics of rodent-derived and human-derived rHEV strains collected in Hong Kong.</p><p dir="ltr">Rodent surveillance detected that 5.2% of street rodents in Hong Kong were positive for rHEV RNA, with Kowloon recording the highest rodent rHEV activity.

This study showed that there was only a partial spatial relationship between districts with high rodent rHEV positivity rates and districts where human rHEV cases were reported in Hong Kong. Phylogenetic analysis showed that all human rHEV cases in Hong Kong belonged to rHEV subtype II.b, and most of them clustered within a phylogenetic group named LCK-3110-like. However, only 18.2% of street rodents in Hong Kong clustered within the LCK-3110-like group, indicating that not all rodent strains are associated with human infections in Hong Kong.</p><p dir="ltr">Subsequently, surveillance of food, livestock, dogs, and cats showed no positive rHEV RNA, indicating that rHEV may not be transmitted through a foodborne pathway or through intermediate hosts.

Therefore, animal and cell culture models were performed. The results showed that rodent-derived rHEV strains could productively infect immunocompromised rats and primary rat hepatocytes, but not HepaRG cells. This human hepatocyte-like cell line could not support productive replication of rodent-derived rHEV strains in Hong Kong, whereas the human-derived strain consistently showed detectable viral load.

This indicates that host barriers may limit rodent rHEV from crossing to humans, which also reflects the observed fact that fewer than 60 human rHEV cases have been reported worldwide. However, because only a limited number of strains were used in cell and animal models, further studies using more human- and rodent-derived strains should be conducted.</p><p dir="ltr">Overall, this study showed that rHEV is widely circulating among rodents in Hong Kong and that it is highly diverse, comprising two distinct subtypes.

Foodborne and intermediate-host transmission routes are considered to pose a lower risk of human rHEV infection. To assess whether host barriers make rodent rHEV difficult to infect humans, more <i>in vivo</i> and <i>in vitro</i> studies are needed. These approaches will help clarify the transmission route of rHEV from rodents to humans and improve assessment of its public health risk.</p>