Researchers from Universidade de Lisboa, Lisboa, Portugal reported on the association of MAP infections in cattle and wildlife as well as MAP presence in soil in a small region of Portugal called Charneca do Infantado, Companhia da Lezíria. Their findings were published in the journal Environmental Pollution February 2024 (it is not Open Access).
ABSTRACT
Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of paratuberculosis, a chronic infection affecting ruminants and other species worldwide. Information on the ecological factors that increase infection risk at the livestock-wildlife-environment interface remains scarce. Thus, this work aimed at determining which factors modulate the exposure of a mammal community within a Mediterranean agro-forestry farmstead to MAP. Through field, molecular and ecological modeling approaches, MAP prevalence, distribution and spatial risk at the livestock-wildlife-environment was estimated in the study area by screening 436 samples (cattle, n = 150; wildlife, n = 206; soil, n = 80). Using molecular detection of IS900 as proxy, MAP was identified in ten wild mammal species. Being a central prey of mesocarnivores in Portugal, the high prevalence of MAP in the wild rabbit (19%) may be related with red fox’s (22%). MAP was also detected in cattle managed in the farmstead (animal and herd prevalence, 54% and 100%) and in soil (44%), which may perpetuate intraspecies and interspecies transmission. Wildlife diversity showed a positive influence on MAP presence in wild mammals, while wildlife abundance showed a negative effect. Land use variables exerted distinct degrees of impact upon MAP detection in specific groups of mammals: mixed forest cover showed positive influence on carnivores, and shrubland showed positive effect on wild rabbits. The prevalence of MAP in cattle showed a negative influence on the detection of MAP in lagomorph, which may stem from wild rabbit lower density and avoidance of cattle areas. Based on explanatory variables, the spatial prediction of MAP occurrence in wildlife indicated two hotspots with increased exposure risk but future studies are needed to confirm this projection.
This work represents the most comprehensive molecular survey of MAP occurrence and determinants in Mediterranean agroecosystems leveraging the principles and tools of community ecology, debating potential biological and ecological effects underlying MAP transmission.
COMMENTS
This novel study reveals an association between the rate of MAP infection in cattle and wildlife. It remains to be determined if the infection spreads only one-way, i.e., cattle to wildlife, or both directions. Other studies have suggested that some wildlife are dead-end hosts (not passing sufficient numbers of MAP in feces to cause infection in other animals) while others, especially rabbits, can be sources of infection for livestock. The study detected MAP in the soil by IS900 PCR. As such, it is not possible to say of the MAP was alive or dead, and thus it’s impossible to know if MAP-contaminated soil is a risk for animal or human infection. Regardless, this study clearly illustrates that MAP is a concern for many more animals than livestock which heightens the importance of programs to control MAP.
Our website has more information specifically about MAP infections of wild ruminants, and both domestic and non-domestic nonruminants (including humans).