Detection of avian nephritis virus and chicken astrovirus in Nigerian indigenous chickens

Abstract

Avian nephritis virus (ANV) and chicken astrovirus (CAstV) are widely distributed in poultry flocks worldwide, causing growth retardation. However, these avian astroviruses have not been previously diagnosed in poultry species in Nigeria. Real-time reverse transcriptase-polymerase chain reaction (rRTPCR) and reverse transcriptase-polymerase chain reaction (RT-PCR) were used for detecting ANV and CAstV in gut contents of apparently healthy Nigerian indigenous chickens. The rRT-PCR assay detected ANV and CAstV in 12 of 13 (92.3%) and 7 of 13 (53.9%) gut content pools, respectively. Using two different primer pairs which amplified approximately 2500 base pairs (bp) and 560 bp fragments in the capsid and polymerase genes of ANV and CAstV, respectively, the RT-PCR assay detected specific ANV and CAstV gene sequences in 4 of 5 (80%) and 2 of 3 (66.7%) rRT-PCR-positive samples in that order. The detection of ANV and CAstV in 8 to 20 week-old Nigerian indigenous chickens indicates that these viruses are probably endemic in the flocks or the environment. This study not only represents the first detection of ANV and CAstV in Nigerian poultry, it is the first report establishing the presence of these two viruses in indigenous chickens.

Key words: Avian nephritis virus, Chicken astrovirus, rRT-PCR, RT-PCR, Nigerian indigenous chickens.