Screening of SRLV in herds in mid-Eastern Poland

Abstract

The aim of the study was to evaluate the epidemiological condition of SRLV infections in nucleus flocks of sheep. The surveillance of Lentivirus infections was conducted in sheep flocks from the mid-Eastern part of Poland: the area of Lubelskie, Świętokrzyskie and Podkarpacie provinces. Ninety eight flocks were chosen for a detailed analysis. They included 6,470 mother ewes belonging to 15 breeds and lines: Polish Merino sheep, Polish Lowland sheep, Wielkopolska sheep, Żelaźnieńska sheep, Uhruska sheep, Olkuska sheep, Polish Heath sheep, Świniarka sheep, Polish Pogorze sheep, Podhale Zackel sheep, Black-headed sheep, Ile de France, Berrichon du Cher, BCP and SCP. The identification of the infected animals and the assessment of the epidemiological condition of the flocks was carried out using a serological analysis of blood serum samples. The assay of MVV-specific antibodies in blood serum was performed using the ELISA test. The results obtained showed that the highest rate of flocks with at least one animal with a positive serological response was in the Podkarpacie Province (71.43%), and the lowest rate (27.03%) was observed in Lubelskie Province. The analysis of the rate of the sheep infected with SRLV indicated that the greatest number of seropositive animals was highest in Podkarpackie Province (19.9%), which corresponds to the results for the flocks, and was significantly higher (p ≤ 0.01) than in Świętokrzyskie Province (11.35%) and Lubelskie Province (9.20%). The flock size turned out to be a factor which significantly influenced the prevalence of SRLV infections. The prevalence was highest (13.6%) in the flocks exceeding 100 sheep, and decreased together with the decreasing number of heads in the flock. It must be stressed that the problem of SRLV infections is very complex and depends on many factors. Therefore it is necessary to carry out a detailed diagnosis of the factors leading to expansion of the virus in sheep flocks before developing flock protection programs...