Genetic relateness of Haemophilus parasuis among reference strains and Chinese epidemic isolates

Abstract

Haemophilus parasuis is the causative agent of Glassers disease and a commensal coloniser of the porcine upper respiratory tract. Multiple complex factors, including the early weaning of piglets and the management of high health status farms, make it a re-emerging agent, responsible for a recent increase in the prevalence and severity of disease in pigs in China. However, little genetic information is known about Chinese epidemic isolates. In this study, a phylogenetic method for genotyping the H. parasuis population with available Chinese epidemic isolates and reference strains from different origins is presented. Phylogenetic analysis confirmed that there are at least two different genotypes in H. parasuis population and a unique Chinese lineage with virulence results in the previous epidemics.