Molecular And Serological Detection Of Newcastle Diseasevirus In Backyard Chicken Production System In Woliso District, Ethiopia

Abstract

Newcastle disease is one of the most important respiratory diseases. It is an infectious viral disease of domestic chicken and other species of birds regardless of variation in sex and age. It causes economic losses such as low growth rate and production, high expense on prevention and treatment, and high morbidity and mortality rate. Despite of these facts, no research report is available on Newcastle disease in the current study area. Therefore, A cross-sectional type of study was conducted with the objective of detecting Newcastle disease virus, using molecular and serological methods in Woliso district, South West Shewa zone, Oromia regional State from December 2018 to November 2019. Out 37 kebeles in the district, six kebeles were randomly selected. Convenience sampling method was used for swab and blood sample collection. For rRT-PCR detection, total of 76 pooled (380 individual) swabs and for serology, 348 serum samples, total of 728 sample collected .Real-time RT-PCR was done targeting matrix (M) gene, while indirect ELISA test was performed to detect anti-bodies against NDV and to determine its anti-body titer. Viral RNA extraction was conducted and rRT-PCR amplification was performed in SDS 7500 fast real time PCR machine (Applied Biosystems, USA), while ELISA test was performed using (ID.vet innovative version 2, Louis Pasteure-Grabels, France) procedures. In rRT-PCR test, 86.8% (66/76 pooled=330/380 individual) were positive for NDV, in indirect ELISA test 37.64 % (131/348) animals were positive and anti-body titer ranging from 998.01 to 11735.9 with mean value of (1761.9088) was scored. Standard deviation of 2592.42160 and percentage CV of 147% was scored. The mean antibody titer was significantly different (F = 1.993, P=0.0079) (Table 2) among the kebeles where the samples were collected. From the finding of this research, we conclude that both real-time PCR and indirect ELISA tests detected presence of the NDV, indicated circulation of the virus and heterogeneousity of anti-body titer in the study area. Therefore, further molecular characterization and epidemiological investigation should be carried out to distinguish circulating NDV genotype and associated risk factors respectively and also vaccine program should be scheduled and vaccination should be provided in the study area to prevent outbreak and economic loss that would occur.