Soroprevalência de Maedi-visna em rebanhos ovinos do estado do Maranhão, Brasil* Seroprevalence of Maedi-Visna in sheep flocks State of Maranhão, Brazil

Although it has been reported in several states, no information about Maedi-Visna (MV) in the state of Maranhao is available. The aim of the present study was to determine the seroprevalence of Maedi Visna Virus (MVV) in sheep flocks of the three most important sheep rearing areas from Maranhao State, Brazil. We surveyed 1.495 blood samples from sheep older than six months, of both sexes and various breeds. The samples were collected from 83 herds of 23 municipalities present in the Central, East and North regions of Maranhao. The immunodifusion agar gel (micro-AGID) performed serological diagnosis of infection MVV. The statistical analysis was performed by Fisher’s test, using Epi Info. It was found an overall prevalence of MVV infection of 0,7% (CI95%:0,4-1,3%) the ovines and prevalence of 0,5% (CI95%:0,1-1,4%), 0,7% (CI95%:0,2-1,8%) e 1% (CI95%:0,3-2,4%) in the Central, East and North regions, respectively. In relation to sex, there wasn’t a significant difference (P>0.05) between males (0,5,%, CI95%:0-2,7%) and females (0,8%, CI95%:0,4-1,4%), as well as in relation to genetic comparing sheep purebreds (1,5%, CI95%:0,4-8,1%), crossbred (1%, CI95%:0,4-2,0%) and SRD (0,3%, IC95%:0,04-1,1%). In relation to age wasn’t observed significant difference. It has concluded that infection with MVV is present in the studied population in low prevalence. This is the first record of MVV in sheep in the State of Maranhao. Considering the low prevalence is necessary to prevent the introduction and spread of the virus between flocks by requiring negative tests for MVV and disposal of positive sheep.