Current strategies for eradication of paratuberculosis and issues in public health

Paratuberculosis is a regional chronic enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP). The first complete description of this disease was made in 1895, but previous reports on clinical cases compatible with this entity can already be found in the literature of early 1800s. Its obvious similarities with tuberculosis gave it the name of paratuberculosis, although it was clearly recognized it was not the same entity as that caused by mammal tuberculosis mycobacteria. Eradication has been considered the ideal goal for control of paratuberculosis, but the lack of efficient diagnostic tools and the high costs involved in testing and culling approaches have shifted the focus to control given the better benefit/cost ratios of more conservative strategies like vaccination. Up to now the control of paratuberculosis has been driven by its negative effects on the ruminant farming industry, however recent growing discussion on its links with human regional enteritis might require control strategies changes if a zoonotic role is considered by Public Health authorities. Paratuberculosis was described nearly 40 years earlier than what is usually considered the first full type description of human regional chronic enteritis or inflammatory bowel disease (IBD) which is pathologically a similar entity. No microbiological evidence was found to link both entities until the 1980s in spite of a number of more or less serious attempts. Afterwards there have been numerous studies showing the association of MAP with human IBD. Microbiological, pathological, immunological, therapeutic and epidemiologic associations have not been considered proof of causality and, currently, no widely accepted consensus has been reached about the etiologic role of MAP in human cases. This puts ruminant farming under suspicion and causes a difficult balance between Public Health precaution and practical control measures.