Small ruminant lentiviruses in goats in southern Italy: Serological evidence, risk factors and implementation of control programs

Small ruminant lentiviruses (SRLVs) can drastically affect milk production in goat flocks and only an early detection can control and prevent their spread. Since SRLVs are responsible for persistent infections, antibody screening is the most valuable tool to identify infected animals. ELISA is recommended as the election test both for its sensitivity and for its ability to detect low antibody titers, thus identifying infected animals earlier than agar gel immunodiffusion (AGID). In the present study, an investigation was conducted to assess the SRLV seroprevalence in goat flocks in southern Italy and a transversal comparative study was carried out through the analysis of the possible risk factors influencing SRLV spread. A total of 4800 sera from 1060 flocks were analyzed and overall seroprevalences of 18,64% and 51,69% at animal and herd levels, respectively, were observed. Both the region and the herd production systems were able to affect seroprevalence, differently from the herd size, probably because the mean number of goats per herd is low and the semi-intensive management is similar regardless of the dimensional class of each herd. In particular, meat producing herds showed the higher seroprevalence, as a result of the poor sanitation and low animal monitoring in comparison to milk producing herds, where animals are managed twice daily and the relationship between dams and kids is checked to guarantee an adequate quantitative/qualitative milk yield. In the absence of vaccines or effective treatments, health preventive management and seroepidemiological investigations are the only successful approach to restrict SRLV spread as observed in countries were official/voluntary control programs are carried out.