Serological and Molecular Study of Newcastle Disease Virus in Village Chickens in Selected Rift-Valley Areas, Ethiopia

Abstract

Newcastle Disease (ND) is a serious and commonly fatal viral poultry disease, which is widely distributed throughout the world. In most developing countries including Ethiopia, ND is the most important disease causing huge economic losses. A cross sectional study was conducted in February 2014 in village chickens at three selected districts in and around rift valley lakes of Ethiopia to determine the prevalence of Newcastle disease virus (NDV) by serological and molecular methods. A total of 155 sera and 155 swab samples were collected from village chickens in Bishoftu, Tikur wuha and Ziway districts. The sera samples were analyzed by Competitive-ELISA. ND viruses were isolated from the tracheal swab specimens, through inoculation in embryonated chicken eggs and were characterized genetically by using molecular methods. Real-time RT-PCR targeting a conserved region of the M gene was employed to amplify all APMV1. M-gene positive samples were further analyzed by Real-time RT-PCR targeting F-gene to specifically amplify the virulent strains. The overall sero prevalence of ND was 11.6% with no statistically significant differences between the study districts at 95% confidence level. Thirteen isolates were positive for APMV1 out of which 38.4% (5/13) were virulent NDV strains. This study provides important information on serological and virological profile of NDV and highlights the importance of continuous surveillances to better understand the epidemiology of the disease.

Molecular Investigation for Matrix Gene of Newcastle Disease Virus in Non-vaccinated Village Chickens in Central Rift Valley of Oromia, Ethiopia

“…Even though, the distribution of the disease differs among the study areas in Eastern Shoa Zone using qRT-PCR analysis with statistically significance difference (p < 0.05), [12] reported an overall prevalence of 26.7% by using rRT-PCR for fussion (F) gene assay from Adama and Bishoftu which is in a close resemblance with our current findings (21.42%) when it was analyzed only for Adama and Bishofitu. In addition, using a rRT-PCR for M gene study conducted by [11] in three selected districts (Batu, Bishoftu and TikurWuha) in rift valley areas revealed an overall prevalence of 8.4% which is less than the current finding and this could be due to the small area coverage. Even though the negative results from the qRT-PCR test in Bishoftu and Bote seem strange, a molecular and serological study conducted for NDV from Iran in non-vaccinated village chicken also showed negative result on qRT-PCR for M gene assay but positive reaction on HI test [19].…”

“…The result of the present study (15.48%) was higher than the findings of other researches done by serological detection method in Eastern Shoa and Kersana Kondaltity district with an overall seroprevalence of 5.9% and 5.6%, respectively [7,20]. In another serological study conducted in selected areas in rift valley an overall sero-prevalence of 5.6% was reported [15] and 11.6% [11] from which one can discern out that the results under the present study, molecular tool, outweighs the results of the former studies by serological (ELISA) method. The overall discrepancy of the findings might be due to variations on management system that may serve as a stress factor that favor infection or the diagnostic tools used.…”

“…Sample size was calculated based on the prevalence of 38.4%, as previously reported by [11], using 95% confidence level and 5% marginal error. A formula according to [16] was used to determine the required sample size as indicated below:…”

“…The choice of matrix gene detection in NDV screening is due its highly conserved nature in the NDV genome where matrix gene assay is able to detect most of NDV isolates [10]. Despite the wide spread problem of ND in Ethiopia in general and Oromia in particular [7,11,12], there is limited information about the genetic profile of NDVs circulating in backyard poultry in Ethiopia. Therefore, the aim of this study was to detect the existence of Newcastle Disease virus by molecular tool in non-vaccinated village poultry in central rift valley of Oromia, Ethiopia.…”

Molecular and Serological Detection of Newcastle Disease Virus in Native Chickens from Selected Live Bird Markets in Batangas, Philippines

“…The main necropsy findings observed in the sampled chickens (11 birds) were multifocal tumorous lesion in the intestines, which may suggest potential visceral Marek's disease, Lymphoid leukosis, reticuloendothelisios, intestinal parasitism or other neoplastic diseases. Seropositive birds but without clinical signs of ND maybe an indication that these birds have previously been infected by non-virulent strains or have survived outbreaks of a virulent NDV strains (Terefe et al, 2015).…”