Rat Hepatitis E Virus Isolates Cluster among Urban Norway Rats (Rattus norvegicus) across a Roadway

Area of Science:

• Environmental Health
• Virology
• Urban Ecology

Background:

• Hepatitis E virus (HEV) is a significant cause of acute hepatitis globally.
• Recent human HEV cases linked to urban rats raise concerns about zoonotic transmission.
• The role of urban rat populations as a reservoir for HEV remains under-investigated.

Purpose of the Study:

• To determine if urban Norway rats (Rattus norvegicus) in Vancouver, Canada, serve as a source of HEV infection.
• To investigate the prevalence and distribution of rat HEV within an urban rat population.

Main Methods:

• Collection and testing of urban Norway rats for HEV presence.
• Analysis of HEV isolates for genetic relatedness and geographic clustering.
• Correlation of HEV infection status with rat physical characteristics and social structures.

Main Results:

• Fifteen percent of tested Norway rats were positive for rat HEV.
• HEV infection prevalence was associated with increased rat body length and familial groupings.
• Rat HEV isolates showed distinct geographic clustering, with a major roadway acting as a barrier to spread.

Conclusions:

• Urban Norway rats in Vancouver harbor HEV, indicating a potential source for human exposure.
• Geographic clustering suggests limited HEV transmission across the roadway, impacting rat population dynamics.
• Findings underscore the public health risk posed by rat HEV and the importance of minimizing human-rat contact and excreta exposure.