Maedi-Visna: Sero-prevalence and risk factors in sheep population of South Wollo and North Shewa Zones, Ethiopia

Maedi-Visna (MV) is a chronic disease of adult sheep characterised by progressive interstitial pneumonia and other syndromes such as meningo-encephalitis, indurative mastitis, and arthritis. The study was conducted to determine the serological epidemiology and associated risk factors of Maedi-Visna in the highland of the North Shewa and South Wollo zones of the Amhara region, Ethiopia. A total of 807 serum samples were collected randomly from purposely selected areas and examined using an indirect enzyme-linked immunosorbent assay to screen specific antibodies against Maedi-Visna. The data were analysed using logistic regression. The overall seroprevalence of Maedi-Visna was 11.7%. The highest and lowest seroprevalence were in Basona-Werena (19.2) and Legambo (6.1%) districts, respectively. As per peasant associations, the highest and lowest seroprevalence were in the Agricultural Research Centre (63.5%) and Kormargefya (0.8 %), respectively. Despite the variation in prevalence level, the disease was insidiously disseminated to all the other study districts and peasant associations. The final multivariable logistic model identified age OR = 5.04 (95% CI: 1.19–21.43), production system OR = 6.96 (95% CI: 3.79–12.78) and body condition score OR = 10.12 (95% CI: 3.63–28.19) as the most important risk factors in relation to MV seroprevalence. This finding showed a higher prevalence of Maedi-Visna in research centre and ranches, which can be a source of Maedi-Visna virus infection in other parts of sheep producing areas. Therefore, strict and regular screening tests should be carried out during the introduction of new flocks and before the distribution of crossbreed rams, particularly from ranches and research centres to smallholder farmers

Evaluation of immune response of small ruminant flocks to ovine Pasteurellosis and Peste Des Petits Ruminants vaccines in North Shewa, Ethiopia

The present study was conducted to evaluate the flock immune response of small ruminants to ovine pasteurellosis Bio type A and Peste des petits ruminants (PPR) vaccines and to determine their effects on the morbidity and mortality of animals due to ovine pasteurellosis and PPR from October 2017 to November 2019 in selected districts of the north Shewa Zone, Ethiopia. A total of 553 serum samples were collected and examined by using the Competitive Enzyme-Linked Immunosorbent Assay and an indirect haemagglutination inhibition test for PPR and ovine pasteurellosis antibodies, respectively. Based on the results, the number of animals with an antibody titer of 1:10 after 28 days and six months of vaccinations of P. multocida Biotype A was 161 (93.1%) and 152 (81.7%), respectively. Also, the positive antibody level (i.e., percent of colour inhibition PI > 50) after 28 days and 12 months of PPRV vaccinations was 82 (86.3%) and 69 (69.7%), respectively. There was a statistical difference (p < 0.001) between the antibody levels after 28 days and six months of vaccination against ovine pasteurellosis and after 28 days and 12 months of vaccination (p <0.01) for PPRV vaccines. During three consecutive years of intervention, out of a total of 2350 study animals, 500 cases (21.3%) showed respiratory signs, out of which 45 (1.9%) died. The PPR and ovine pasteurellosis vaccines applied in the field were effective in developing antibodies above the threshold herd immunity level of 80% and 70% respectively.Periodic vaccination against ovine pasteurellosis and PPR according to the epidemiology of the diseases results in a significant reduction in morbidity and mortality of small ruminants. Therefore, the current ongoing efforts to control ovine pasteurellosis and PPR of small ruminants through vaccination should be encouraged and strict sero-surveillance and monitoring of these diseases should be done side by side