Molecular detection and characterisation of avian paramyxovirus type 1 in backyard chickens and pigeons in Alzintan city of Libya

Avian paramyxovirus-1 (APMV-1) is the causative agent of Newcastle Disease which affects many species of birds leading to high mortality and heavy economic losses among poultry industry worldwide. Newcastle disease is endemic in Libya with frequent outbreaks occurring in commercial and backyard poultry. APMV-1 was isolated and characterised during the outbreak in 2013. In current study, we report another Newcastle disease outbreak that emerged in backyard chickens and pigeons in Alzintan city on March 2015. Two viruses were detected in cloacal swabs from backyard chickens, namely APMV-1/Libya/15VIR5368/2015 and APMV-1/Libya/15VIR5371/2015. Genetic sequencing of these viruses revealed the presence of velogenic APMV-1 belonging to genotype VIIi genetically similar to the viruses isolated on 2013. During the same period, neurologic signs and mortality were noticed in pigeons. Samples of brain tissue were tested by rRT-PCR which revealed presence of velogenic APMV-1 belonging to lineage 4A (GKKRKR*F Lin.4A) or genotype VIb. To the best of our knowledge, this is the first report of the detection and molecular characterization of APMV-1 in a pigeon in Libya. The phylogenetic analysis of the F gene showed 86% identity to isolates from Iran and Egypt. This study may indicate the circulation of APMV-1 within backyard birds and pigeons which may present a threat to commercial poultry. Considering these findings, vaccination of backyard birds and pigeons and further epidemiological studies are strongly strongly recommended.