Host specificity of Avipox viruses: an experimental study with field isolates of fowlpox, pigeonpox and duckpox viruses

Abstract

A study was conducted to determine the host specificity of field isolates of fowl pox virus (FPV), pigeon pox virus (PPV) and duck pox virus (DPV) by giving cross infection. During inoculation of fowl pox virus (FPV) in embryonated chicken eggs, and duck pox virus (DPV) in embryonated duck eggs showed PCR positive during the first passage itself. Inoculation of pigeonpox and duckpox viruses in embryonated chicken eggs required 2–3 initial passages to get the positive results. In the experimental study, all the chicks inoculated with FPV developed pox lesions within 7–9 days post infection. Similarly, all the pigeons inoculated with PPV developed pox lesions within 5–9 days. Likewise, all the ducklings inoculated with DPV developed pox lesions within 5–6 days. In cross infection study when FPV, PPV and DPV were inoculated in heterologous hosts no lesions were developed. Histopathological examination of the scab samples of infected birds revealed intracytoplasmic eosinophilic inclusion bodies. Among the visceral organs the lungs showed congestion and haemorrhages with proliferation of lymphoid cells around the bronchioles, the heart showed capillary congestion between the myofibrils, hydropic degeneration and fatty changes in the liver and renal tubular epithelium. The scab samples of infected birds showed positive results for APV by PCR; but the biopsy samples collected from the inoculated site of the heterologous hosts showed PCR negative. It was concluded that field isolates of fowl pox virus (FPV), pigeon pox virus (PPV) and duck pox virus (DPV) exhibited host specificity and did not produce cross infection in heterologous hosts.