Subclinical circulation of Chicken infectious anaemia virus- A Sero-molecular study.

Chicken infectious anaemia-an important immunosuppressive viral disease of chicken-gained much attention in the recent past. Based on huge mortality and production loss observed in the fast-growing poultry sector, the present study aimed to find out the current status of the chicken infectious anaemia virus (CIAV), among chicken flocks in the Punjab state of India by sero-molecular study. The sera from the blood samples were tested for anti-CIAV antibodies by indirect ELISA and also compared with haematological parameters. DNA from sero-positive samples underwent PCR amplification, sequencing and phylogenetic analysis of the most conserved genomic region (VP3 gene) to detect viraemia in asymptomatic birds. The serological study using indirect ELISA showed a high sero-positivity of 77.27% in chicken flocks. Additionally, the present study also revealed the high molecular evidence (72.54%) of CIAV in apparently healthy birds. Genetic analysis showed that all CIAVs have conserved VP3 genes without any nucleotide substitutions, indicating presence of CIAV and its subclinical circulation among apparently healthy flocks. The wide distribution of CIAV among birds may be the reason for huge mortality and production loss. Further, it is suggested that studies be conducted to find out the co-involvement of CIAV with other immunosuppressive microbial agents and the immunosuppressive effect of CIAV in apparently healthy birds. Also, its role in vaccine failure and outbreaks of various other avian diseases needs to be explored.

Detection and molecular characterization of chicken infectious anaemia virus in young chicks in Punjab region of north-western India.

Chicken infectious anaemia (CIA) is an important viral disease of chicken causing significant immunosuppression and severe anaemia worldwide. Occurrence of severe disease and mortality is noticed in young chicks (2-3 weeks). Vertical mode of transmission increases chance of infection and persistence of virus among the infected flocks. The current study was conducted in Punjab state for confirmation and genetic characterization of CAV among chicken flocks of various poultry farms. DNA was extracted from the tissue samples and subjected to polymerase chain reaction (PCR) of VP1 gene and whole genome. PCR products were further sequenced for confirmation of chicken infectious anaemia virus (CIAV) genome in the clinical samples. PCR amplification of DNA from the tissue samples yielded expected product size of 1350 bases of VP1 gene and 2.3 kb of whole genome. Out of 16 commercial poultry farms, 11 were confirmed with presence of CIAV, and out of 65 birds, 39 were found positive (60%) for CIAV genes. Among the various organs, the presence of viral gene was detected at highest level in thymus when compared with other organs. It is concluded that chicken infectious anaemia virus detected from Punjab state is closely related to other Indian isolates and neighbouring countries which necessitates need of more intensive studies with a greater number of samples for implementing effective control measures.