# High prevalence of Duck Hepatitis B virus-associated coinfection in Southwest China

## TL;DR

This study found that Duck Hepatitis B virus is highly prevalent in Southwest China and often co-occurs with other hepatitis viruses and bacterial infections in ducks.

## Contribution

The study reveals the high prevalence and co-infection patterns of Duck Hepatitis B virus with other viruses and bacteria in diseased ducks.

## Key findings

- Duck Hepatitis B virus had the highest infection rate (86.01%) among five hepatitis viruses in diseased duck livers.
- Over half of DHBV-infected ducks were co-infected with Duck Hepatitis A virus.
- DHBV co-infection was positively correlated with other hepatitis viruses and bacterial infections.

## Abstract

Currently, five types of duck hepatitis viruses have been documented, and they are all associated with liver disorders. However, the prevalence of their coinfections involving these viruses remains largely uncertain. Herein, we screened the prevalence of the five types of hepatitis viruses from A to E in 143 samples of diseased duck livers during 2019–2021 in Southwest China. We found the highest infection ratio (86.01%, 123/143) of duck hepatitis B virus (DHBV) among all five types of hepatitis viruses. Importantly, a large portion of DHBV-associated coinfections were identified, with 52.85% (65/123) co-infected with Duck Hepatitis A virus (DHAV), 39.84% (49/123) with tentative Duck Hepatitis D virus (DHDV), and 34.96% (43/123) with Duck Hepatitis E virus (DHEV), respectively. Interestingly, a positive correlation between the DHBV-positive rate and the infection rates of the other co-infected hepatitis viruses was revealed, suggesting the importance of DHBV in duck hepatitis virus co-infection events. To understand the situation of bacterial secondary infection, the prevalence of bacterial infection was simultaneously screened using standard 16S rRNA PCR, and hepatitis virus-associated bacterial infections were observed. Collectively, these findings revealed a high prevalence of DHBV-related coinfections and its association with the coinfection of the other duck hepatitis viruses and bacteria. In the future, it is important to study the impact of DHBV co-infection events on disease severity, thereby evaluating the necessity of vaccine development for DHBV.