Molecular Epidemiological Investigation on Avian Reovirus in Some Provinces of China from 2020 to 2021
In recent years,avian reovirus(ARV)has been increasingly and widely prevalent in white feather broilers in China,bringing great economic losses to broiler breeding enterprises in China. As ARV is prone to mutation and recombination,it would be of great significance to comprehensively investigate its molecular epidemiological characteristics. In order to investigate the genetic variation characteristics of ARV in white feather broilers in China from 2020 to 2021,253 suspected ARV infected samples were collected from Shandong,Hebei,F(xiàn)ujian,Anhui,Liaoning and Jiangsu provinces to detect positive samples by RT-PCR,followed by σC gene(1 088 bp)sequencing,against which,the distribution and proportion of different ARV genotypes were analyzed. The results showed that 157 positive samples were detected by RT-PCR,with a total positive detection rate of 62.1%,and that in each province was from 44.4% to 77.3%. All the 157 positive samples were divided into 6 genotypes,including 61 genotype 1(38.85%),41 genotype 2(26.11%),15 genotype 3(9.56%),9 genotype 4(5.73%),30 genotype 5(19.11%),and 1 genotype 6(0.64%);38 out of 61 genotype 1 samples belonged to the same sub-branch as the standard ARV vaccine strain(S1133),and the other 23 fell into a separate sub-branch with 4599 reference strain. In conclusion,ARV was prevalent in broilers in China to certain extent;the prevalent ARV genotypes were complex,and there were genotype 1 variant strains,so sufficient protection could not be provided by current vaccine strains anymore,which indicated that surveillance for ARV infection should be further strengthened,its prevalence and variation should be evaluated,immunization strategies should be adjusted,and research and development of disease prevention technologies and products such as new vaccines should be accelerated. The above study on the molecular epidemiological characteristics of ARV in some provinces of China supported the prevention and control of ARV infection in China,and provided a basis for the research and development of novel vaccines against any variant strains.