Newcastle disease (ND), caused by virulent avian paramyxovirus type 1, is one of the most important diseases responsible for devastating outbreaks in poultry flocks in Ethiopia. However, the information about genetic characteristics of the Newcastle disease viruses (NDVs) circulating in commercial chickens and wild birds is scarce. In this study, we characterized isolates obtained from ND suspected outbreaks during 2012–2014 from poultry farms (n = 8) and wild pigeons (n = 4). The NDVs isolated from pathological specimens, through inoculation in embryonated chicken eggs, were characterized biologically by conventional intracerebral pathogenicity indices (ICPI), and genetically on the basis of Phylogenic analysis of partial F-gene sequences (260 bp) encompassing the cleavage site. The ICPI values of isolates from chickens ranged from 0.9 to 1.8; whereas, the ICPI of pigeon isolates was 1.4. All isolates contained multiple basic amino acids at the deduced cleavage site of fusion protein, which is a typical feature of virulent viruses. Phylogenic analysis of the partial cleavage site of F-gene (260 bp) indicated that all the sequences of viruses obtained from pigeons were identical and clustered within the genotype VIh while the sequences of viruses obtained from chickens were clustered together within the genotype VIf. The similarity between the viruses obtained from chickens and those obtained from pigeons ranged from 82.5 to 85.6 %. This suggests that different sub genotypes of genotype VI are circulating in chicken and wild pigeon population in Ethiopia. This warrants further study to understand the role of wild birds in the epidemiology of NDV in Ethiopia and as well highlights the importance of continuous surveillances both in wild birds and domestic poultry.
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.
Newcastle disease ( ND ) is a major infectious disease of poultry caused by a virulent strain of Avian Paramyxovirus type-1 ( APMV-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 conduct molecular surveillance of ND Virus and identify potential risk factors for nonvaccinated village chicken in Central Rift Valley of Oromia, Ethiopia. A total of 84 pooled swab samples, each made from pools of 5 swabs for analysis, from cloacal and tracheal sites of chickens in the Central Rift Valley were collected, and RNA was extracted to carry out real-time quantitative polymerase chain reaction. Out of the 84 pooled swab samples tested for M-gene, 13 (15.48%) samples were found positive for APMV-1. The prevalence of ND in males was found to be 16.10% and that in females was 14.67%. Although the overall ND prevalence was 15.48% (13/84), the highest prevalence was recorded in Adama, 42.86% (6/14), and no positive case was observed in Bote and Bishoftu ( P < 0.05), while intermediate prevalence was obtained from Batu, Arsi-negele, and Shashemene ( P > 0.05). In general, the present study provides important information on the epidemiology of ND based on M-gene assay in Central Rift Valley of Oromia, Ethiopia, and highlights the importance of implementing molecular surveillances practice in live poultry markets and village chickens.
Introduction Brucellosis is a neglected bacterial zoonosis with serious veterinary and public health importance throughout the world. A cross-sectional study on animal brucellosis was conducted aiming to estimate seroprevalence and molecular detection. Methods Blood samples were collected from a total of 4274 individual animals (cattle, small ruminants and camel) from 241 herds/flocks for serology and PCR. Serum samples were tested using multispecies I-ELISA. Blood clots from seropositive animals were also tested for brucellosis via PCR. Additionally, 13 vaginal swab samples were collected from animals (2 from bovine and 11 from small ruminants) with recent abortion history for bacterial isolation and molecular detection. Results The overall individual animal and herd level seroprevalence was 3.95% (169/4274) and 18.26% (44/241) respectively. The animal level seroprevalence at species level was 1.58% (47/2982), 8.89% (97/1091) and 12.44% (25/201) in bovine, small ruminants (sheep and goat) and camel, respectively. Herd level seroprevalence were 5.43% (10/184), 52.08% (25/48) and 100% (9/9) in bovine, small ruminant and camel, respectively. The animal level seroprevalence of bovine from intensive and extensive systems was 1.10% (31/2808) and 2.87% (5/174) respectively. Blood clots tested for brucellosis via PCR were negative by RT-PCR. Brucella species was isolated from 6/13 (46.15%) vaginal swab samples cultured on Brucella selective agar, and shown to be B. melitensis using Real-Time PCR. Conclusion Overall, seropositivity for camels was higher than what has been reported previously. Also, there was a notable difference in this study in cattle seroprevalence when comparing extensive with intensive systems, with the extensive system having much greater seropositivity.
Background 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. Newcastle Disease Virus (NDV) is an enveloped, non-segmented, single-stranded negative-sense RNA virus with a helical morphology whose genome has six open reading frames (ORF) which encode for the following proteins: nucleoprotein (NP), phosphoprotein (P), matrix protein (M), fusion protein (F), hemagglutinin-neuraminidase (HN) and RNA-dependent RNA polymerase (L). The aim of this study was to detect matrix gene (M-gene), for NDV by molecular tools and identify its risk factors in non-vaccinated village chicken in Central Rift Valley of Oromia, Ethiopia.Methods 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 real-time quantitative polymerase chain reaction (qRT-PCR). A real-time reverse transcriptase polymerase chain reaction (rRT-PCR) along with the quantification was also done for 10 positive qRT-PCR samples that were having high concentration of viral load Ct. value.Results Out of the 84 pools of five swab samples tested for M-gene using qRT-PCR, 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%. 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.Conclusions In general, the present study provides important information on the epidemiology of NDV based on M-gene assay in Central Rift Valley of Oromia, Ethiopia, and highlights the importance of implementing surveillances and biosecurity practices in live poultry markets and village chickens.
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