Sui, Chaoge, Cui, Hao, Ji, Jun, Xu, Xin, Kan, Yunchao, Yao, Lunguang, Bi, Yingzuo, Zhang, Xinheng, and Xie, Qingmei
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. synoviaeby screening samples from Central China. Subsequently, 129 M. synoviaestrains were isolated, with a positive rate of 50%. Moreover, a higher incidence of M. Synoviaeinfections 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. synoviaegenotyping. 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 of the vlhAgene (76–421 nt) assigned the majority of the occurring strains as being from group 6, and others from groups 2 and 3. Results identified that these isolates were of 6 types: A (38aa), D (23aa), E (19aa), I (28aa), J (20aa), and L (35aa), based on the size of the PRR region analysis. Furthermore, most of the isolates (81.4% were identified as type L. Additionally, the epidemic types included only I and L in 2017; however, the types rose to 5 (A, D, E, I, L) in 2018 and rose to 6 (A, D, E, I, J, L) in 2019. These data showed the genotype diversity of M. synoviaein Central China. The high rate of positive flocks suggests the urgent need to take real-time supervisory controls of this Mycoplasma species in avian flocks.