Multiple studies have been carried out to assess the prevalence of infection with Mycobacterium avium subsp. paratuberculosis (MAP) in farmed animals. However, most studies are not directly comparable because different diagnostic tests were used. True prevalences can be calculated from apparent prevalences if test-accuracy estimates for the diagnostic test used are available. The objective of the present study was to conduct a review of MAP prevalences among farmed animals in Europe.

Data about prevalence of MAP in all farmed animal species were included from a variety of literature databases. Information on target population and study design, tests used and apparent prevalences was recorded, and subsequently true prevalences were calculated when possible. A full critical review of the included studies indicated that although a wide range of studies have been conducted, credible true prevalences could often not be calculated. Based on a few studies in which the prevalences appeared plausible, it was concluded that prevalences of MAP would have to be guesstimates based on available data. Among cattle, approximately 20%, or a minimum of 3 to 7% were infected in several countries. Between-herd prevalence estimates appeared to be >50%. No countries appear to have published sufficient information to state that they have a low or a zero prevalence of MAP infections. In goats and sheep the only within-herd prevalence guesstimates were 14% and 2%, respectively, but these figures were based on Norwegian populations only. The between-herd prevalence guesses were >23%, based only on figures from Switzerland.