Rapid identification of chicken anemia virus in Nigerian backyard chickens by polymerase chain reaction combined with restriction endonuclease analysis

Chicken infectious anemia (CIA) has not been routinely diagnosed in other avian species apart from commercial chickens. A sensitive polymerase chain reaction (PCR) combined with restriction endonuclease (RE) analysis was used for the detection and characterization of chicken anemia virus (CAV) in backyard chickens (Gallus gallus domesticus) in Nigeria. Using a pair of primers designed to amplify a 733 bp fragment in the VP1 (capsid protein) gene of CAV, the PCR assay detected CAV DNA in 9 of 12 serum samples from apparently healthy backyard chickens. RE digestion of the purified PCR products of commercial and backyard chickens with CfoI yielded two separate restriction endonuclease patterns, suggesting that Nigerian backyard chicken CAVs differed from the commercial chicken isolates at the nucleotide sequence level. Results of RE analysis also suggested that the backyard chickens contained a mixed population of CAV strains. These findings confirm that backyard chickens are susceptible to CAV infection and could also harbor the virus.