Prevalence of Mycobacterium avium Subsp. paratuberculosis in Feral Pigeons (Columba livia) Associated with Difficulties Controlling Paratuberculosis in a Bovine Herd (Fighting Bull Breed)

SIMPLE SUMMARY: This study reports the 10 years (2011–2020) follow-up of a cattle herd, with a high prevalence of paratuberculosis (PTB) cohabiting with a population of pigeons. After 6 years without tests, the herd returned to a high prevalence, and the PTB program control was revised. Likewise, the presence of MAP in feral pigeons was studied to evaluate their role as a transmitter and/or reservoir, as well as their influence on controlling the PTB. Antibodies values according to the optical density (OD) determined by ELISA increased each year and could be used to isolate herds close to the cutoff point to improve PTB control. The maintenance of ELISA tests, even though there are no positive animals, is essential for the success of the PTB control. PCR results positive against MAP samples of intestine, foot skin, and feces were observed in pigeons. The follow-up carried out in this study made it possible to establish the wild pigeons as mechanical vectors of PTB in cattle after confirmation of MAP in the foot, as well as the possibility of a possible in intestine and feces. Although future studies should be carried out to clarify the true importance of these findings in the PTB control program in cattle, the control of pigeons in farm could be important. ABSTRACT: A bovine herd with a high prevalence of paratuberculosis (PTB) cohabiting with a population of pigeons was studied (2011–2020). After finding the disease in 2011, annual monitoring was performed in 2012–2014 by obtaining blood samples for ELISA and intradermal tuberculinization (IT) tests for Mycobacterium avium subsp. paratuberculosis (MAP). Positive animals were eliminated. PTB prevalence dropped from 10% to 0% but returned to similar values (9.5%) after 6 years without tests. In all animals, Ac values according to the optical density (OD) determined by ELISA increased each year and could be used to isolate herds close to the cutoff point to improve PTB control. Possible reservoirs were considered after evaluating the little success of the PTB control program, and the population of feral pigeons was studied. Specifically, 10% of the pigeon population (n = 13) was necropsied. Samples of intestine, feces, and foot skin for PCR study for MAP and samples of terminal intestine for histopathological analysis were taken. Eleven pigeons were PCR-positive against MAP, in the intestine (10/11), foot skin (3/11), and feces (1/11). The presence of MAP in pigeon feet could demonstrate its role as a mechanical disseminator of PTB, while the presence in pigeon intestine and feces could also suggest its role as a reservoir.