Prevalencija tripanosomoze i njezinih prijenosnika u deva u pokrajini Fentale u Jugoistočnoj Šoi u Etiopiji

A cross-sectional study was conducted to determine the prevalence of camel trypanosomosis and assess the distribution and dynamics of the vectors responsible for transmission of the disease in five localities of Fentale district from September 2008 to January 2009. Parasitological examination was conducted using the microhaematocrit centrifugation technique (MHCT) and examination of Giemsa stained blood smears. The only species of trypanosome identified was Trypanosoma evansi with a prevalence of 4.7% by MHCT and 4.4% by blood smear. The prevalence was higher in male (6.8%) than female (4%) camels. With regard to age, calves (less than 2 years of age) were negative; the prevalence is high (7.7%) in young camels (between 3-4 years of age) and 4% in adult camels (older than 4 years of age). However, the difference in prevalence between sex and age groups was not statistically significant (P>0.05). The prevalence using blood smears was found to be different between different localities; the highest being 7.8% for Kobo and the lowest 2% for Haro kersa. The mean packed cell volume (PCV) of Trypanosoma evansi positive camels (22.43%) was significantly lower than that of negative camels (28.13%) (P0,05). Prevalencija na temelju pretrage krvnih razmazaka bila je različita u životinja iz različitih područja. Najveća prevalencija dokazana je u životinja na području Kobo (7,8%), dok je najmanja (2%) bila na području Haro Kersa. Srednja vrijednost hematokrita u invadiranih deva bila je statistički značajno manja (22,43%) u usporedbi s neinvadiranim devama (28,13%) (P<0,05). Više od 99% ulovljenih kukaca pripadalo je muhama roda Stomoxys. Preostali su kukci pripadali rodovima Tabanus, Chrysops i Lyperosia. Najveći broj kukaca bio je ulovljen tijekom rujna, a najmanji tijekom prosinca. Razumljivo je da je prevalencija nametnika Trypanosoma evansi bila viša tijekom kišnih razdoblja. Autori smatraju da se dobiveni nalazi ne mogu odnositi na sva područja kao i sva godišnja doba pa zato predlažu da se nastave istraživanja, koja će obuhvatiti različita razdoblja te ulogu različitih prijenosnika bolesti

Seroprevalence of Newcastle disease and other infectious diseases in backyard chickens at markets in Eastern Shewa zone, Ethiopia

This study was conducted to estimate the seroprevalence of Newcastle disease (ND), Pasteurella multocida (PM) infection, Mycoplasma gallisepticum (MG) infection and infectious bursal disease (IBD), and to assess the level of concurrent seropositivity during the dry and wet seasons of the year 2010. A total of 234 and 216 sera were collected during the dry and wet seasons respectively from unvaccinated backyard chickens at four live poultry markets in two Woredas (Districts) of Eastern Shewa Zone, Ethiopia, and were tested using commercial enzyme-linked immunosorbent assay (ELISA) kits. The overall seroprevalence of ND, PM, MG, and IBD was 5.9%, 66.2%, 57.7% and 91.9% respectively during the dry season, and 6.0%, 63.4%, 78.7% and 96.3% respectively during the wet season. The seroprevalence of MG was higher (P < 0.001) during the wet season than during the dry season and higher (P = 0.002) in Adami-Tulu-Jido-Kombolcha (ATJK) Woreda (74%) than in Ada’a Woreda (60%). Area and season had no significant effect on the seroprevalence of ND, IBD and PM, indicating the widespread presence of those pathogens throughout the year in the study area. Of all the chickens tested, 85.6% had antibodies concurrently to more than one of the pathogens investigated. Birds were concurrently seropositive to more diseases during the wet season (median = 3) than during the dry season (median = 2) (P = 0.002). As serology is not able to distinguish between strains, further studies are warranted to better understand the circulating strains, their interactions and their economic effect on backyard poultry production in Ethiopia.The study was done under the framework of the FSP project [GRIPAVI 2006-26] funded by the French Ministry of Foreign and European Affairs (MAEE).http://ps.oxfordjournals.orghb2016Production Animal Studie

Serological and molecular investigation of Newcastle disease in household chicken flocks and associated markets in Eastern Shewa zone, Ethiopia

Cross-sectional survey for Newcastle disease (ND) were conducted in nonvaccinated household flocks of village chickens to assess serological and virological ND status in households and associated live bird markets. In total, 1,899 sera and 460 pools of cloacal and tracheal swabs were sampled and tested using a commercial enzyme-linked immunosorbent assay (ELISA) and real-time reverse transcriptase polymerase chain reaction (rRT-PCR), respectively. Additionally, paired cloacal and tracheal swabs from 1,269 individual chickens were collected from markets and tested using RT-PCR. The prevalence of households with at least one seropositive chicken was higher during the dry season (27.4 %) than during the wet season (17.4 %) (P = 0.003). Viral genome was detected in 14.2 % of households during the wet season using a fusion (F) gene assay and in 24.2 % of households during the dry season using a polymerase (L) gene assay that targets both class I and class II viruses. At the markets sampled, overall bird level prevalence was 4.9 % for period 1 (F gene assay), and 38.2 % and 27.6 % for periods 2 and 3, respectively (L gene assay). Partial sequencing of the F gene (239 bp) cleavage site indicated that the majority of the circulating strains exhibited motifs specific to virulent strains. Seroepidemiology coupled with molecular analysis can be a useful tool to assess the status of NDV infection. The village chicken population in Ethiopia is endemically infected with virulent NDV that pose a significant threat to emerging small- and medium-scale commercial poultry production.The French Ministry of Foreign and European Affairs (MAEE).http://link.springer.com/journal/11250hb2016Production Animal Studie

New avian paramyxoviruses type I strains identified in Africa provide new outcomes for phylogeny reconstruction and genotype classification

Newcastle disease (ND) is one of the most lethal diseases of poultry worldwide. It is caused by an avian paramyxovirus 1 that has high genomic diversity. In the framework of an international surveillance program launched in 2007, several thousand samples from domestic and wild birds in Africa were collected and analyzed. ND viruses (NDV) were detected and isolated in apparently healthy fowls and wild birds. However, two thirds of the isolates collected in this study were classified as virulent strains of NDV based on the molecular analysis of the fusion protein and experimental in vivo challenges with two representative isolates. Phylogenetic analysis based on the F and HN genes showed that isolates recovered from poultry in Mali and Ethiopia form new groups, herein proposed as genotypes XIV and sub-genotype VIf with reference to the new nomenclature described by Diel's group. In Madagascar, the circulation of NDV strains of genotype XI, originally reported elsewhere, is also confirmed. Full genome sequencing of five African isolates was generated and an extensive phylogeny reconstruction was carried out based on the nucleotide sequences. The evolutionary distances between groups and the specific amino acid signatures of each cluster allowed us to refine the genotype nomenclature. (Résumé d'auteur

Epidemiology of Newcastle disease in village chickens in Ethiopia : risk factors, molecular characterization and role of poultry markets

Village chickens contribute considerably to the economy and to the nutritional requirements and livelihood of many rural farmers in developing countries across the globe. The spread of highly pathogenic avian influenza H5N1 into Africa during 2005/6 drew attention to the neglect of avian disease surveillance and research in countries such as Ethiopia, in which predominantly village chickens are reared. Several infectious and non-infectious diseases have limited the productivity of village chickens in Ethiopia, among which Newcastle disease (ND), caused by avian paramyxovirus serotype 1 (APMV-1), is the most important. Newcastle disease virus (NDV) causes subclinical to severe disease depending on the virus strain. To better understand the epidemiology of the disease, a study was performed in the mid-Rift Valley area of Oromia region, Ethiopia, to estimate seroprevalence and incidence of NDV exposure, identify risk factors, evaluate market trade movements and characterize circulating NDV strains. Repeated serological surveys in live bird markets revealed that village chickens were concurrently seropositive for several important infectious diseases, particularly during the wet season. The seroprevalence of ND, Pasteurella multocida infection, Mycoplasma gallisepticum infection and infectious bursal disease virus infection were 5.9%, 66.2%, 57.7% and 91.9%, respectively, during the dry season, and 6.0%, 63.4%, 78.7% and 96.3%, respectively, during the wet season. This underlines the need for a holistic approach to control of infectious disease in village chickens, and further studies are warranted to better understand the circulating strains, their interactions and their economic effect on village poultry production. A cross-sectional study using a multistage random sampling design with repeated sampling periods was done in households, along with a structured questionnaire. The prevalence of household flocks with at least one seropositive chicken was higher during the dry season (27.4%) than during the wet season (17.4%) (P = 0.003) while the proportion of flocks in which viral genome was detected was 24.2% and 14.2 %, respectively. The prevalence of NDV genome detection in individual birds at markets varied from 4.9 % to 38.2, depending on the period of sampling and the reverse transcriptase polymerase chain reaction (RT-PCR) technique employed. Multilevel mixed-effect logistic regression models were used to identify risk factors for NDV seropositivity and for incidence of NDV exposure. Reduced frequency of cleaning of poultry waste, larger flock size and use of an open water source (pond or river) for poultry were associated with increased risk of NDV exposure or seropositivity, while maintaining a closed flock and the use of a grain supplement was associated with lower odds of seropositivity or a lower risk of NDV exposure. Molecular characterization and phylogenetic analysis, based on complete F and HN gene sequencing, was done on NDV isolates obtained at markets and villages. The circulating viruses had amino acid motifs characteristic of virulent strains, indicating endemic circulation of virulent virus in village chickens which poses a threat to improvement of village chicken production and emerging small-scale commercial poultry production. The strains clustered in genotype VI, branching with viruses from subgenotype VIb that commonly affect pigeons, although clustering apart on pairwise distance analysis. The apparent poor biosecurity in village chickens and history of isolation of pigeon variant viruses from domestic chickens in Ethiopia suggest that pigeons could play a role in the epidemiology of ND in village chickens. Further surveillance and virus characterization is required to shed more light on this. Bayesian methods were used to evaluate the performance of two commercial enzyme-linked immunosorbent assay (ELISA) kits (a blocking and an indirect ELISA) and haemagglutination inhibition (HI), in the absence of a gold standard, for their ability to detect antibodies to NDV in chicken serum from villages and live bird markets. The blocking ELISA had the highest sensitivity (Se) of 96.3% (95% posterior credible interval (PCI): 88.1; 99.8%), and specificity (Sp) of 98.9% (95% PCI: 97.8; 99.9%), while the HI had Se of 81.6% (95% PCI: 71.8, 91.9%), and Sp of 96.1% (95% PCI: 95.1; 96.6%). The indirect ELISA also had high Se (95.2%; 95% PCI: 88.5; 99.0%) but had very low Sp (8.9%; 95% PCI: 6.4, 11.8%). There is therefore a need for evaluation of commercial kits before their wider use in village chickens under field conditions. Market trade movement patterns for live chickens were described, using social network analysis, for two different periods during the year 2010, representing high (period one) and low (period two) seasons for poultry trade. The study revealed that the networks exhibited scale-free characteristics with weak connectivity of the markets and low density of the networks. The density for the two periods was not difference (P = 0.29), although a somewhat higher number of markets and links were observed during period one than period two. The low density of the networks indicates that in the event of infectious disease outbreaks in surroundings of the respective markets, the risk of its spread to many others would likely be fairly low. Nevertheless, the close similarity of NDV isolates from distant markets in the study area suggests that markets could play a role in the spread of infectious poultry diseases. A few markets were more central in the networks, in terms of their betweenness and out-degree; these markets could be considered for targeted surveillance, while those markets with high in-degree, mainly situated in the larger urban centres, can be considered for surveillance that involves regular poultry traders.Thesis (PhD)--University of Pretoria, 2012.Production Animal StudiesPhDUnrestricte

Assessment of retrospective rabies suspected cases registered at two hospitals, community and traditional healers’ knowledge, attitude and practices in south Ethiopian pastoralist

Despite of available protective rabies vaccines for both human and animal, transmission of rabies from animals to people continues in Africa and Asia. Every year, over 59,000 people are estimated to die from the disease globally. Most of industrialized countries in Europe and North America have eliminated rabies from domestic dog populations. However, in the majority of developing countries, rabies remains endemic in domestic dog and poorly controlled. To understand rabies situation in pastoralist and agro-pastoralists area of southern Ethiopian, retrospective data on 431 rabies suspected animal bite cases registered at Bule Hora and Yabello Hospitals were collected and reviewed. Moreover, the knowledge, attitude and practice of 107 selected community members and 55 traditional healers were assessed. Out of 431 cases, 55.7% and 24.4% were &lt; 15 and between 16-25 years age group, respectively. There were more male 55.5% cases than female 44.5%. Only 32% of cases registered at Yabello Hospital received post exposure prophylaxis (PEP), whereas the remaining referred to other health facilities. Ninety eight percent (98 %) of animal responsible for the bite was dog and the remaining were cat, fox and donkey. Most of bites were occurred in March-June (36.2%) and November-February (35.5%). Out of interviewed participants 87.8% of them know rabies and 83.2% were able to mention rabid animals’ symptoms. The 78.5% of participants did mention how rabies transmitted to dog and 88.1 % of them described dog as main source of infection. The 91.6% of participants told us that rabies is transmitted to human by rabid animals’ bite and 94.3% of them believe that rabies is treatable disease and the major means of prevention is traditional treatment. Almost all traditional healers mention that the symptom of rabies in human and animals, and its way of transmission; however 90.9% of them believe that traditional treatment as effective means of rabies control. Interview result of both community members and traditional healers indicated that most of the rabies cases treated by the traditional healers. Health service providers have to make PEP vaccines available for bite victims and need to raise awareness of the local communities through health education about rabies and animal bite management.Keyword: Retrospective Study; Rabies; South Ethiopia; pastoralist

Evaluation of enzyme-linked immunosorbent assays and a haemagglutination inhibition tests for the detection of antibodies to Newcastle disease virus in village chickens using a Bayesian approach

Newcastle disease (ND) is an endemic disease in village chickens in Ethiopia with substantial economic importance. The sensitivity (Se) and specificity (Sp) of a blocking enzyme-linked immunosorbent assay (bELISA, Svanova Biotech), indirect ELISA (iELISA, Laboratoire Service International) and haemagglutination inhibition (HI) test for ND virus (NDV) antibody detection were evaluated in a Bayesian framework in the absence of a gold standard test, on sera collected from unvaccinated chickens kept under the village production system in household flocks and at markets in two woredas (i.e. districts) of the Eastern Shewa zone, Ethiopia. The outcomes of the iELISA test differed dramatically from those of the two other tests with 92% of the samples testing positive as compared with less than 15% for bELISA and HI. iELISA results were also inconsistent with previous estimations of Newcastle serological prevalence. The information provided by the iELISA test was thus considered as highly unreliable, probably due to an extremely low specificity, and thus not considered in the Bayesian models aiming at estimating serological prevalence and test performance parameters. Bayesian modelling of HI and bELISA test results suggested that bELISA had both the highest Se (86.6%; 95% posterior credible interval (PCI): 61.8%; 98.5%), and the highest Sp (98.3%; 95% PCI: 97.2%; 99.5%), while HI had a Se of 80.2% (95% PCI: 59.1%; 94.3%), and a Sp of 96.1% (95% PCI: 95.1%; 97.4%). Model selection and the range of the posterior distribution of the correlation between bELISA and HI test outcomes for truly seropositive animals (median at 0.461; PCI: ?0.055; 0.894) suggested a tendency for bELISA and HI to detect the same truly positive animals and to fail to detect the same truly positive animals. The use of bELISA in screening and surveillance for NDV antibodies is indicated given its high Se and Sp, in addition to its ease of automation to handle large numbers of samples compared to HI. The latter can be used as confirmatory test where an ELISA test with moderate or low specificity is used although the likely positive dependence with bELISA implies that HI and bELISA provide similar information on truly positive animals. Evaluation of commercial ELISAs is indicated before their wider use in village chicken populations to avoid erroneous inferences. (Résumé d'auteur