Mycobacterium avium subsp. paratuberculosis (Map) is an obligate pathogen and parasite of animals, so in theory it could be eradicated by removal of all infected animals. That is the principle in which the "testing and culling" control programs are based. However, the capacity of Map to survive for long periods of time outside the host allows him to withstand a periodic lack of suitable hosts, remaining in the environment and posing a threat of new infection to other healthy animals. In this context, we conducted a study to determine the environmental burden of Map in a goat farm infected with paratuberculosis and subjected to a control program.Goats in the farm were divided in two groups as a part of the control program: "infected" (not included in the control program) and "free" (under the control program). Environmental samples were taken from the "free" area (where the controlled animals were) and from the milking room; soil, mud, drinking troughs and the water supply system were analysed. These samples were processed for direct extraction of DNA and culture of Map and other mycobacteria. DNA specific fragment for genus Mycobacterium was detected in several places from the free area and from the milking room; but Map specific fragment IS900 was only detected in the milking room, the only shared area between both "infected" and "free" groups. Atypical mycobacteria were cultured from soil and water, but no Map was isolated.The presence of Map specific fragment IS900 in the milking area may suggest the cleaning in this zone was not exhaustive enough, and thus animals might become infected there. However, the impossibility of culturing Map raises the question whether they are viable or not.

Sponsorship

Attendance to this Congress was sponsored by the EU-funded project SSPE-CT-2004-501903.