Characterization of isolated pigeon paramyxovirus-1 (PMV-1) and its pathogenicity in broiler chickens

Characterization of isolated pigeon paramyxovirus-1 (PMV-1) and its pathogenicity in broiler chickens were studied. Two hundred and thirty-two samples collected from 50 unvaccinated pigeons lofts suspected to Newcastle disease from private houses and bird markets from Ahvaz, Iran. Swab samples from cloaca and oropharynx of live pigeons and from trachea, lung, liver, spleen, kidney, brain, proventriculus and cecal tonsil of dead pigeons suspected to ND were collected. Isolation of the PPMV-1 was performed through intra-allantoic inoculation of 9- to 11- day-old embryonated chicken eggs. The RNA extraction and cDNA synthesis were conducted. With PCR, multiplication of cleavage site of F gene was carreid out and PCR products were sequenced and phylogenetic comparison on isolates was performed. For pathogenecity study of isolated PPMV-1, one hundred sixty day-old broiler chicks were divided into four equal groups. Groups 1 and 2 chicks vaccinated against ND by B1 vaccine at nine days. Groups 3 and 4 were kept as unvaccinated control groups. Groups 1 and 4 chicks were challenged with 10⁵EID₅₀ of highest virulent isolated PPMV-1 by ocular route at day 29. The results indicated PPMV-1 is enzootic in Ahvaz pigeons and all isolates were virulent Newcastle disease virus with 112KRQKR*F117 motif. For study pathogenicity of pigeon isolate in chickens, they challenged with most virulent isolate, showed respiratory signs, conjunctivitis and in some cases depression and lethargy. In conclusion, isolated PPMV-1 is a virulent NDV and can infect chickens and produce mild ND in unvaccinated chickens.