Subtypes of genotype 3 hepatitis E virus in pigs

Area of Science:

• Veterinary Virology
• Public Health Microbiology
• Molecular Epidemiology

Background:

• Hepatitis E virus (HEV) is a zoonotic pathogen with significant public health implications.
• Pigs are recognized as a major reservoir for HEV, posing a risk of transmission to humans.
• Understanding the genetic diversity and prevalence of HEV in swine populations is crucial for implementing effective control strategies.

Purpose of the Study:

• To determine the prevalence and genetic characteristics of Hepatitis E virus (HEV) RNA in pigs from Eastern and South Western China.
• To investigate the distribution of different HEV genotypes and subtypes within these pig populations.
• To explore the potential origins and transmission dynamics of HEV in China based on molecular data.

Main Methods:

• Collection and analysis of fecal and bile samples from pigs in abattoirs across Eastern and South Western China between 2006 and 2011.
• Detection of HEV RNA using reverse transcriptase polymerase chain reaction (RT-PCR).
• Sequence analysis of detected HEV strains to determine genotypes and subtypes, and to assess genetic relatedness.

Main Results:

• HEV RNA was detected in 4.8% of pigs (HEV-4) and 0.07% of pigs (HEV-3) across the study period.
• HEV-4 showed a significantly higher prevalence compared to HEV-3.
• Distinct subtypes of HEV-3 were identified in different regions, with subtype 3a found in South Western China and subtype 3b in Eastern China, exhibiting regional genetic variations.

Conclusions:

• The study highlights the circulation of HEV-3 and HEV-4 in Chinese pig populations, with HEV-4 being more common.
• The identification of distinct HEV-3 subtypes in different geographical regions suggests multiple independent introductions or diverse evolutionary pathways of HEV infection.
• These findings underscore the importance of ongoing surveillance and molecular characterization of HEV in animal reservoirs to inform zoonotic disease prevention efforts.