Small Ruminant Lentivirus Infection in Sheep and Goats in North Portugal: Seroprevalence and Risk Factors

Small ruminant lentiviruses (SRLVs) are transmitted among ovine and caprine species. This disease is a severe problem for small ruminant production, not only for animals' well-being but also for flocks' efficiency. The main aim of this research was to quantify the seroprevalence and associated risk factors for SRLV infection in the northern region of Portugal. Samples were collected from a total of 150 flocks, of which 129 (86.0%; 95% CI: 80.67%-91.33%) had at least one seropositive animal. Out of 2607 individual blood samples, 1074 (41.2%) were positive for SRLVs. Risk factors associated with SRLV infection were species (caprine), age (>2 years old), flock size (>100 animals), production system (intensive), food production system (milk), type of activity (professional), participation in livestock competitions (yes), replacement young ewe bought (yes), and natural feeding management (yes). This knowledge empowers the implementation of effective preventive measures. Overall, biosecurity measures should be promoted and implemented with the main aim of reducing viral transmission and reducing the prevalence of this disease. We recognise that government authorities should promote and audit voluntary control and eradication programs in small ruminant flocks in the region studied.

A serosurvey of Mycobacterium avium subsp. paratuberculosis infection of goats in the North of Portugal

To better understand the epizootiology of caprine paratuberculosis in the North of Portugal, a cross-sectional study was conducted from 2014 to 2015. The seroprevalence and risk factors for Mycobacterium avium subsp. paratuberculosis (Map) seropositivity were evaluated. Antibodies against Map were determined by a commercial ELISA. In 936 sera tested from 56 goat herds, 120 (12.8%, 95% CI: 10.8-15.1%) goats and 34 (60.7%, 95% CI: 47.6-72.4%) herds were positive. Risk factors for seropositivity were investigated by logistic regression models. The odds of Map seropositivity were found to be higher for animals with clinical signs, OR = 5.1 (95% CI: 2.7-9.6%), animals belonging to herds with previous wasting disease, OR = 2.3 (95% CI: 1.1-4.8%), and accumulation of manure in the herd, OR = 3.1 (95% CI: 1.7-5.7%). The potential risk factors identified in this study support the current recommendations for the control of paratuberculosis in these and other animals.