Prevalence and risk factors associated with Maedi-Visna infection in sheep in the State of Maranhão, Brazil

Michelle Lemos Vargens,Daniel Praseres Chaves,Mylena Andréa Oliveira Torres,Rosiane De Jesus Barros,Margarida Paula Carreira De Sá Prazeres,Analy Castro Lustosa Cavalcante,Tiago Da Silva Teófilo,Erlin Cely Cotrim Cavalcante

doi:10.33448/rsd-v10i5.14440

Abstract

In order to determine Maedi-Visna virus (MVV) seroprevalence and risk factors associated with infection in sheep, 445 animals of both sexes and different ages were tested using the Agarose Gel Immunodiffusion technique (IDGA). The animals were divided into two groups: group 1 composed of exhibition animals (n=70) and group 2 composed of animals from properties from the north, east and central mesoregions of the state of Maranhão (n=375). The general prevalence of MVV infection was 2.02%; 1.42% in group 1 and 2.13% in group 2. In the north mesoregion the prevalence was 2.20%, while a total of 40% of the animals living in municipalities for MVV. It was observed that 1.15% of males and 2.23% of females were seropositive (p> 0.20). Regarding breeds, the Dorper (1.66%); Santa Inês (1.67%); White Dorper (33.33%) and Texel (4.34%) were the most affected. This was the only variable among all the risk factors studied that had a significant association in multivariate analysis (p <0.05). MVV infection is present regardless of the purpose of breeding, and the animals are exposed to the same risk of infection. This demonstrates the need to implement public policies for the prevention, control, and eradication of this disease.

Highlights

Maedi-Visna (MV) is a chronic and progressive multisystemic disease that mainly affects sheep (Araújo et al, 2004; Lombardi et al, 2009)
The study was approved by the Ethics Committee in Animal Experimentation of the State University of Maranhão (CEAA/UEMA – 012/2013)
The general prevalence of the Maedi-Visna (MV) found in this study is considered low by Reina et al (2009) (1 to 9%), and is similar to that observed in other states where a semi-extensive breeding system predominates

Summary

Introduction

Maedi-Visna (MV) is a chronic and progressive multisystemic disease that mainly affects sheep (Araújo et al, 2004; Lombardi et al, 2009). It is caused by an RNA virus belonging to the genus Lentivirus, family Retroviridae, subfamily. In the CNS, a histiocytic or lymphocytic inflammatory pattern is predominantly described (Gayo et al, 2018). Animals with a histiocytic pattern are recognizable by the ELISA test, whereas sheep with a lymphocytic lesion pattern may go unnoticed as seronegative and are probably a remnant source of infection (Gayo et al, 2017). Transmission can occur mainly through respiratory exudates and secretions, most often facilitated between animals kept in confinement periods (Callado et al, 2001; Cortez-Romero et al, 2013)

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