Epidemiological Characteristics and Genetic Diversity of Chicken Infectious Anemia Virus (CIAV) in Guangdong...

Chicken infectious anemia virus (CIAV) causes immunosuppression in poultry, leading to substantial global economic losses through both vertical and horizontal transmission. Since 2014, frequent outbreaks have been reported in southern China; however, the epidemiology of CIAV in Guangdong Province remains poorly defined. Between July 2018 and March 2022, we collected 105 tissue samples and 786 serum samples from poultry in nine cities. PCR/qPCR assays targeting the VP1 gene confirmed CIAV infection, and positive tissues inoculated into MSB1 cells yielded four isolates (GDHZ1, GDHZ2, GDJM, GDLF). Phylogenetic analysis demonstrated that GDHZ1, GDJM, and GDLF clustered within clade A1, whereas GDHZ2 belonged to clade A2. All isolates shared glutamine (Q) at position 394, together with virulence-associated amino acid signatures (75V, 89T, 125L, 139K, 141Q, 144E). Serological testing indicated a high prevalence, with 627 of 786 samples positive (79.77%). The relatively low proportion of virus-positive tissues and successful isolations may reflect viral tropism or limitations in detection sensitivity. These findings enhance understanding of CIAV molecular epidemiology in Guangdong and provide evidence to inform surveillance, vaccination strategies, and control measures.