Epidemiology and risk factors of Mycobacterium avium subspecies paratuberculosis in semi-extensive dairy sheep and goat farms of Apulia, southern Italy

Paratuberculosis (PTB) is a well-documented chronic and sometimes fatal infection that affects the small intestine of ruminants both in captive and free-ranging living conditions. Although the infection has been detected on small ruminant farms worldwide, epidemiological and risk factor information regarding Mycobacterium avium subspecies paratuberculosis (MAP) infection on semi-extensive sheep and goat farms is generally still scarce, particularly in the Mediterranean area and in Italy. This paper reports the epidemiological findings and risk factors of the infection on semi-extensive sheep and goat farms in Apulia. It particularly focuses on the involvement of biological, structural and management factors, as well as the farmers’ socioeconomic data as predisposing causes of PTB, and investigates their possible connection with the survivability of the infection. The true seroprevalence values of MAP on semi-extensive Apulian sheep and goat farms are reported and the risk factors causing the spread of infection analyzed. Data were collected through a two-year survey over the whole regional area, involving 419 farms, 16,903 sheep and 9369 goats. The epidemiological results showed a true seroprevalence of 66.2% for flocks and of 9.7% at the animal level. Analysis of the risk factors showed that the spread of infection occurs via several concomitant biological, managerial, and farmer-related factors. The survey highlighted the need for urgent and suitable control plans providing guidelines to help Apulian farmers and their veterinarians contain and eliminate the disease, prevent biological risks for animal and humans as well as negative economic effects on the regional livestock sector.