Epidemiological investigations and locally determined genotype diversity of Mycoplasma synoviae in Central China from 2017 to 2019.

Mycoplasma synoviae (M. synoviae) has been identified worldwide to cause respiratory diseases, infectious synovitis, airsacculitis, and eggshell apex abnormalities (EAA) in commercial chickens, which results in substantial economic losses to the poultry industry. Therefore, in this study, 258 flocks were investigated between 2017 and 2019 for M. synoviae by screening samples from Central China. Subsequently, 129 M. synoviae strains were isolated, with a positive rate of 50%. Moreover, a higher incidence of M. synoviae infections was in layers (74.1%) than in broilers (20%) in this study. The 5′-end conserved segment of the variable lipoprotein hemagglutinin A (vlhA) gene of these isolates was then cloned and sequenced because it is a common genomic target identified so far for M. synoviae genotyping. Genotyping of all isolates was based on the phylogenetic analysis and length analysis of the proline-rich-repeat (PRR) regions, respectively. Phylogenetic analysis based on 5′-end conserved segment...