Cross-sectional survey of brucellosis and associated risk factors in the livestock-wildlife interface area of Nechisar National Park, Ethiopia.

A cross-sectional survey was carried out to investigate the seroprevalence of ovine and bovine brucellosis in the livestock-wildlife interface area of Nechisar National Park, Ethiopia. Furthermore, producer's knowledge about brucellosis and its zoonotic potential was assessed using a structured questionnaire. A total of 268 cattle and 246 goat sera were collected from 50 herds and 46 flocks and subjected to Rose Bengal test (RBT) and enzyme-linked immunosorbent assay (ELISA) in parallel to detect anti-Brucella species antibodies. Positive reactions were further confirmed with compliment fixation test (CFT). Flock and herd level seroprevalence rate was 12.8% (95% CI 4.8-25.7) and 32.0% (95% CI 19.5-46.7) in goats and cattle, respectively. An overall animal-level seroprevalence of 4.5% (95% CI 2.25-7.86) and 9.7% (95% CI 6.44-13.89) was recorded for goats and cattle, respectively. Seroprevalence showed an increasing trend with age, where adult cattle > 2 years. Goats (> 1 year) recorded relatively higher seroprevalence, but the differences were not statistically significant. Similarly, female cattle and goats recorded a relatively higher seroprevalence, 11 and 5.6%, respectively, compared to males but the difference was not significant. However, a significant (P < 0.01) variation of seroprevalence was noted for parity (bovine), higher in animals in second parity, and abortion history, in both species, higher in animals that experienced abortion. Interviews revealed lack of awareness about brucellosis and food safety related to the zoonotic potential from consuming raw animal products (milk and meat). Ninety-eight percent of respondents did not consider handling abortion material is risky, and only a very low proportion (8%, n = 50) was able to mention limited zoonotic diseases (anthrax and Taenia cysticercosis) could be transmissible to people. The study indicated that brucellosis is endemic in domestic animals in the interface area and calls for further broad epidemiological investigation of the disease in livestock, human and wildlife following 'one health' unified research approaches beside enhancing public awareness.

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.

Peste Des Petits Ruminants in the Middle East: Epidemiological Situation and Status of Control and Eradication Activities after the First Phase of the PPR Global Eradication Program (2017-2021).

Peste des petits ruminants (PPR) is a burdensome viral disease primarily affecting small ruminants, which is currently targeted for eradication by 2030 through the implementation of a Global Control and Eradication Strategy (PPR GCES). The PPR GCES, launched in 2015, has strongly encouraged countries to participate in Regional PPR Roadmaps, designated according to the Food and Agricultural Organization of the United Nations (FAO) and World Organisation for Animal Health (WOAH) regions and epidemiological considerations, with each targeted by dedicated meetings and activities. Following the conclusion of the first phase of the PPR Global Eradication Program (PPR GEP) (2017-2021), the present work focuses on the disease situation and status of the eradication campaign in the fourteen countries of the PPR GCES Middle Eastern Roadmap as well as Egypt. PPR is endemic to or suspected to be present in most of the region, except for Bahrain, which, as of 2021, is preparing to apply for official recognition as being free of PPR. Some substantial shortcomings are observed in surveillance and disease reporting, as well as in the implemented control strategies, most notably vaccination. Since many of these limitations are shared by many of the investigated countries, the international cooperation and harmonization of control efforts appears crucial to making PPR eradication attainable in the Middle East.

Efficacy of albendazole against nematode parasites isolated from a goat farm in Ethiopia: relationship between dose and efficacy in goats.

A suspected case of albendazole resistance in a goat farm of Hawassa University was examined using faecal egg count reduction test (FECRT), controlled anthelmintic efficacy test and egg hatch assay (EHA) to verify the development of resistance and/or the need for higher doses of the drug in goats than in sheep. The experiment was conducted in 12 sheep (2 groups: treatment versus control) and 24 goats (4 groups: 3 treatments versus control, n = 6; per group) following artificial infection with infective larvae of Haemonchus contortus and Oesophagostomum columbianum. The first group of sheep and goats were treated orally with albendazole at the dose rate of 3.8 mg/kg body weight (i.e. manufacturer's recommended dose for sheep) while the second group of sheep and the fourth group of goats were left untreated. The second and the third group of goats were treated with albendazole at 5.7 and 7.6 mg/kg respectively. The FECRT showed an efficacy of albendazole in goats to be 65.5, 81.4 and 84.1% at the dose rate of 3.8, 5.7 and 7.6 mg/kg body weight respectively while in sheep it was 62% at the dose rate of 3.8 mg/kg. Increasing the dose to 1.5 the sheep recommended dose induced minor improvement of efficacy in goats; however the efficacy was almost the same at 1.5 and twice the dose recommended for sheep. Worm counts at day 15 post-treatment revealed that H. contortus has developed resistance to albendazole. EHA results also supported these findings. On the other hand, O. columbianum was 100% susceptible at all dose levels tested.

Evaluation of the efficacy of anthelmintics sold on Ethiopian markets against Haemonchus contortus in experimentally infected Sheep.

A total of 54 lambs, aged between 6-8 months were experimentally infected with Haemonchus contortus to evaluate the efficacy of different anthelmintic brands sold on Ethiopian markets using the faecal egg count reduction test (FECRT) and controlled anthelmintic efficacy trial. Accordingly four different albendazole (Alzole, Analgon-300, Albenjung_s and Ahshialben-300), two tetramisole (Tetsole and Ashitetra 600) and two tetramisole-oxyclozanide (Tetraclozan sheep and Tetraclozash 900) brands were evaluated at the dosage rates recommended by the manufacturers. Animals were allocated into nine groups of six animals each, and balanced for faecal egg counts (FEC), based on their pre-treatment FEC and treatments were randomized among the groups. One group was kept untreated as a control. Faecal egg count was conducted on day 30 post-infection (day of treatment) and on the 10th day post-treatment. Evaluation of anthelmintics based on FECRT revealed high efficacy (99.55-100% reduction in FEC) for all anthelmintic brands tested against H. contortus. The worm count reduction test using controlled anthelmintic efficacy trial also supported the above finding with 99-100% efficacy of the tested anthelmintics. Therefore, the suspicion on the anthelmintic products as being substandard in quality is not credible, at least, for the brands investigated in this study and it might rather be attributed to under dosing. The need for a good extension system for livestock producers with regard to good anthelmintic usage practices, in light of the inevitable development of anthelminitic resistance, is emphasized. Regular surveillance and laboratory quality evaluation of the anthelmintic products in Ethiopia is indicated.

Field-derived estimates of costs for Peste des Petits Ruminants vaccination in Ethiopia.

In 2015, the OIE and FAO launched a global eradication programme for Peste des Petits Ruminants (PPR). Vaccination is a major component of this strategy yet the costs of implementing a campaign are unknown or based on assumptions without field-based verification necessary for effective economic planning. This study used experiences of attending four PPR vaccination campaigns in Ethiopia to estimate various cost components in pastoral and mixed-crop livestock systems. These components included: cost of vaccine; vaccine transport from the producer to the local storage facility; storage of vaccine at the local facility; delivery and administration of vaccine in the field; opportunity cost of farmer's time to attend the vaccination; co-ordination of vaccination campaign; publicity and mobilisation costs; vaccine wastage from missed shots and vaccine discard. The overall cost of vaccination was approximately 6 Ethiopian birr (ETB) or US$0.2 per animal in the mixed-crop livestock system compared to approximately 3ETB or US$0.1 in pastoral areas. The relative importance of cost components varied in the two systems with farmer time being the largest contributor in the mixed-crop livestock system while field delivery was the main cost in pastoral areas. Notable vaccine wastage was observed particularly through missed shots that were typically between 0 and 10% but as high as 33%. At the national level, the output of the stochastic model showed the cost of vaccination to be highly variable particularly in the mixed-crop livestock system. These results highlight the importance of doing economic assessments of vaccination campaigns and issues that may be compromising efficiency of delivery and vaccine coverage. It is recommended that the framework be used for further economic evaluations of vaccination for PPR and other livestock diseases particularly when limited public or donor funds are being used, and that the approach be expanded to other countries and regions.

Characterization of Newcastle disease virus isolates obtained from outbreak cases in commercial chickens and wild pigeons in Ethiopia.

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.

Analysis of traditional poultry trader networks to improve risk-based surveillance.

Live bird markets and contacts between them through poultry traders are known risk factors in the spread of diseases such as Newcastle disease. A traders' questionnaire survey was used to build networks of chicken movements among 29 shared markets during and outside festive seasons in the Oromia region of Ethiopia. A comparison was made between typologies built using centrality indexes (in-degree, out-degree, in-closeness, out-closeness and random-walk betweenness) and descriptive characteristics of the markets (number of chickens, number and type of sellers and the frequency with which they use different markets). The festive seasons did not appear to have an impact on the network structure, implying that it was not necessary to make structural changes to surveillance targets during these periods. Based on centrality indices, three markets (Meki, Debre Zeit and Adulala) emerged from the typology as being central to the network, which would not have been deduced from their descriptive characteristics alone. These three poultry markets ideally would be chosen in a risk-based type of surveillance system and in targeted control policies.

Household-level risk factors for Newcastle disease seropositivity and incidence of Newcastle disease virus exposure in backyard chicken flocks in Eastern Shewa zone, Ethiopia.

A cross-sectional study with repeated sampling was conducted to investigate potential risk factors for Newcastle disease (ND) seropositivity and for incidence of ND virus (NDV) exposure in household flocks of backyard chickens in Eastern Shewa zone, Ethiopia. Data were collected from 260 randomly selected households in 52 villages in Adami Tulu Jido Kombolcha and Ada'a woredas (districts) using a structured questionnaire, and serum samples from chickens were tested for NDV antibodies using a blocking enzyme-linked immunosorbent assay (ELISA). Sampling took place during September 2009 and the same households were again sampled in May 2010. Household-level seroprevalence and incidence of NDV exposure were estimated in various ways using serological results from the two samplings, flock dynamics, and farmers' reports of ND in their flocks. The risk factors were assessed using multivariable mixed-effects logistic regression models. Household-level seroprevalence at the two sampling times was 17.4% and 27.4%, respectively, and the estimated incidence of household-level NDV exposure during the intervening period ranged between 19.7% and 25.5%. At the first sampling, reduced frequency of cleaning of poultry waste was associated with increased odds of seropositivity (OR=4.78; 95% CI: 1.42, 16.11; P=0.01) while hatching at home vs. other sources (buying in replacement birds, receiving as gift or buying fertile eggs) was associated with lower odds of seropositivity, both at the first sampling (OR=0.30; 95% CI: 0.11, 0.82; P=0.02) and the second sampling (OR=0.23; 95% CI: 0.10, 0.52; P<0.001). The risk of NDV exposure was shown to be higher with larger flock size at the beginning of the observation period (OR=3.6; 95% CI: 1.25, 10.39; P=0.02). Using an open water source (pond or river) for poultry compared to closed sources (tap or borehole) was associated with increased risk of NDV exposure (OR=3.14; 95% CI: 1.12, 8.8; P=0.03). The use of a grain supplement (OR=0.14; 95% CI: 0.03, 0.69; P=0.03) and hatching at home for flock replacement (OR=0.23; 95% CI: 0.10, 0.52; P=0.005) were associated with a lower risk of NDV exposure. Newcastle disease seroprevalence and incidence of NDV exposure were more heterogeneous between villages than between kebeles (aggregations of villages) and woredas in the study area. Further investigation of village-level risk factors would likely improve our understanding of ND epidemiology in backyard chickens.

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.

Gastrointestinal helminths are highly prevalent in scavenging chickens of selected districts of Eastern Shewa zone, Ethiopia.

A cross-sectional survey on gastrointestinal helminths was conducted on 124 chickens raised under traditional management system in two selected districts namely Ada'a and Adamitulu of Eastern Shewa zone, Ethiopia. Of these chickens, 111 (89.5%) were found to harbor one of the five different helminth parasites and 13 (10.48%) were free of helminths parasites. The study also found that 103 (83.0%) and 72 (58.0%) of the examined chickens were invariably infected by diverse species of cestodes and nematodes species, respectively. There was a statistically significant difference (p < 0.05) in the prevalence between cestodes and nematodes of helminths parasites within the same district. The major cestode species recovered form chickens were Raillietina echinobothrida 79 (63.7%), Raillietina tetragona 70 (56.5%), Raillietina cesticillus 50 (40.3%) and Choanotaenia infundibulum 17 (13.7%), Davainea proglottina 10 (8.1%), Hymenolepis contaniana 22 (17.7%) and Hymenolepis carioca 7 (17.7%). The major nematode species encountered were Heterakis gallinarum 47 (37.9%), Ascaridia galli 40 (32.0%), Gongylonema ingluvicola 32 (25.8%), Dispharynx nasuta 5 (4.0%), Heterakis isolonche 11 (8.9%), Allodapa suctoria 9 (7.3%), Capillaria anatis 4 (3.2%) and Heterakis dispar 8 (6.5%). The study also tried to see the prevalence of these parasites in relation with age and sex however, it has no significant difference (p > 0.05) with those risk factors. On the other hand district significantly affect the prevalence of some parasites (p < 0.05). This study strongly suggested that helminthosis is a very serious problem of backyard chickens in eastern Shewa zone of Oromia and appropriate control strategies need to be devised.