Molecular Detection and Assessment of Associated Risk Factors for Newcastle Disease Virus in Non-vaccinated Village Chickens in Central Rift Valley of Oromia, Ethiopia

Abstract

Newcastle disease (ND) is a major infectious disease of poultry caused by a virulent strain of Avian Paramyxovirus – 1. It is a major threat to the poultry industry in many countries of the world including Ethiopia. The aim of this study was to detect Newcastle disease virus by molecular tools and identify its risk factors in non-vaccinated village chicken in Central Rift Valley of Oromia, Ethiopia. For this purpose, a total of 84 pooled in five swab samples from 420 cloacal and tracheal chickens were sampled and RNA was extracted from the 84 pooled samples to carry out qPCR reaction. A conventional PCR along with purification was also done for 10 positive samples that were having best Ct. value in order to send to Germany for sequencing. Out of the 84 pools of five swab samples tested for matrix gene (M-gene) using qPCR, 16.7% (14/84) samples were detected which included 13 positives and 1 negative for NDV. The prevalence of ND in males was found to be 16.10% and that in females was 14.67%. On the other hand, the prevalence of ND was higher in Adult (16.59%) compared to old chicken (11.11%) (p < 0.05). Although the overall ND prevalence was 15.48% (13/84), the highest score was recorded in Adama, 42.86% (6/14), and no positive case was detected in Bote and Bishoftu (p <0.05) while intermediate scores were obtained from Batu, Arsi-negelle and Shashemene. Based on the questionnaire interview, 71.1% (128/180) of the respondents indicated that ND was the leading disease and 98.3% (177/180) indicated that disease occurrence was higher during rainy season. Accordingly, the highest correlation value of R= 0.62 between the monthly rainfall data and disease outbreak was obtained. In general, the present study provides important information on epidemiology of NDV in Central Rift Valley of Oromia, Ethiopia, and highlights the importance of implementing surveillances and biosecurity practices in live poultry markets and village chickens.