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

Abstract

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.