# Burden of rodent-borne viruses in rodents and zoonotic risk in humans in Cambodia

## TL;DR

This study found rodent-borne viruses in Cambodia, especially in urban areas, and identified human exposure risks, highlighting the need for better rodent control and public health measures.

## Contribution

The study is the first to investigate rodent-borne virus prevalence and human exposure in Cambodia, revealing urban-specific zoonotic risks.

## Key findings

- 9.7% of 750 rodents tested positive for at least one virus, with higher rates in urban areas.
- Human seroprevalence for HEV was 24.2%, linked to urban residency and medical history.
- Urban residency and flood-prone areas were key factors in increased virus exposure risks.

## Abstract

Rodent-borne viruses, including orthohantaviruses, mammarenaviruses, and rat hepatitis virus (HEV-C), pose significant health threats to humans, causing severe diseases such as hemorrhagic fevers, respiratory illness, and hepatitis. In Cambodia, data on these viruses remain limited, and their burdens on human health are unknown. This study investigated the presence of these viruses in rodents and assessed potential human exposure across diverse environmental and socio-economic contexts in Cambodia. The study was conducted in urban, semi-urban, and rural areas of Cambodia during the rainy season of 2020 and dry season of 2022. Rodents were screened for viruses using RT-PCR. Human serum samples from the same sites were tested for IgG antibodies using ELISA. Factors associated with virus spillover into humans were analyzed. Among 750 rodents, 9.7% carried at least one virus: 5.2% mammarenavirus, 3.3% orthohantavirus, and 1.9% HEV-C. Infection rates were highest in urban (14.5%), followed by semi-urban (11.9%) and rural (2.1%) interfaces. Mammarenavirus was more prevalent in the rainy season, while orthohantavirus and HEV-C remained consistent across seasons. In humans, seroprevalence was 12.7% for mammarenavirus, 10.0% for orthohantavirus, and 24.2% for HEV. Higher mammarenavirus seroprevalence was associated with urban residency. Orthohantavirus seroprevalence was associated with urban residency, acute hepatitis history, and flood-prone living areas. HEV seroprevalence increased with urban residency, increasing age, and medical condition history. Our findings highlighted the need for rodent control, improved market infrastructure, enhanced waste management, and public awareness of hygiene practices and zoonotic risks, especially in urban high-risk areas.

Rodents can carry viruses that may spread to humans, sometimes causing serious diseases. However, little was known about the presence of these viruses in Cambodia or their potential impact on human health. This study investigated rodent populations across urban, semi-urban, and rural areas and tested both rodents and humans for three key viruses: arenavirus, hantavirus, and hepatitis E virus. The findings confirm the presence of these viruses in rodents and indicate human exposure, particularly in urban areas. Factors such as urban residency and living in flood-prone areas were associated with an increased risk of exposure. These results emphasize the need for improved rodent control, waste management, and public awareness of zoonotic disease risks. A better understanding of virus transmission dynamics will help guide health officials in developing effective strategies to prevent infections and protect communities.