Ecological drivers of Mycobacterium avium subsp. paratuberculosis detection in mongoose (Herpestes ichneumon) using
Mónica V Cunha1,2,3, Luís Miguel Rosalino4, Célia Leão5
1INIAV, IP- National Institute for Agrarian and Veterinary Research, Av. da República, Quinta do Marquês, 2780 -157, Oeiras, Portugal. monica.cunha@iniav.pt.
Abstract:
Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of Johne's disease or paratuberculosis, a chronic infection affecting domestic ruminants worldwide. Despite sporadic reports of MAP occurrence in non-ruminants, information on the risk factors predisposing for infection is still scarce and evidence of transmission paths linking the livestock-wildlife-environment interfaces also remains lacking. In this study, we predicted that environmental, host-related, land use and human driven disturbance factors would modulate carnivore exposure to MAP. To test these hypotheses, we performed a retrospective survey, based on microbiological and molecular methods, in mainland Portugal including five sympatric species from the Herpestidae, Canidae, Viverridae, and Mustelidae families (n = 202) and examined 16 variables as putative predictors of MAP occurrence. Molecular evidence of MAP using IS900 as proxy was demonstrated in 7.43% (95%CI: 4.55-11.9) of surveyed carnivores, the highest proportions being registered for red fox (Vulpes vulpes) (10%; 95%CI: 4.0-23) and Egyptian mongoose (Herpestes ichneumon) (6.0%; 95%CI: 3.2-11). We demonstrate that important species of the Mediterranean carnivore guild, such as stone marten (Martes foina) and common genet (Genetta genetta), may also be exposed to MAP, being this the first time that occurrence in genet is reported. The high proportion of DNA-positive specimens, concurrent with the apparent lack of gastro-enteric lesions and molecular confirmation of IS900 in feces, argue for the presence of subclinical carriers that occasionally shed bacteria, potentially aiding as source of infection to susceptible species and possibly contributing for environmental contamination. Achievement of MAP isolation would prove beyond any doubt that MAP is present in this wildlife population. Ecological modelling results suggested that the probability of MAP infection using IS900 as proxy in mongoose is positively associated with higher altitude and temperature stability, as well as with lower annual rainfall. Density of livestock farms was found not to be a significant predictor, which may indicate that the livestock-wildlife interface is probably not important as an infection route for mongoose.
Insights
Mycobacterium avium subsp. paratuberculosis (MAP) was detected in Portuguese carnivores, with red foxes and Egyptian mongooses showing the highest prevalence. Environmental factors, not livestock density, influenced MAP exposure in mongooses, suggesting wildlife may act as reservoirs.
Area of Science:
- Veterinary Microbiology
- Wildlife Ecology
- Disease Ecology
Background:
- Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease in ruminants.
- Limited data exists on MAP in non-ruminant wildlife and associated risk factors.
- Understanding wildlife exposure is crucial for disease transmission dynamics.
Purpose of the Study:
- To investigate MAP occurrence in Mediterranean carnivores in Portugal.
- To identify environmental, host, land use, and human disturbance factors associated with MAP exposure.
- To assess the role of carnivores in MAP transmission and environmental contamination.
Main Methods:
- Retrospective survey of 202 carnivores from five species (Herpestidae, Canidae, Viverridae, Mustelidae).
- Microbiological and molecular methods (IS900 PCR) to detect MAP DNA.
- Ecological modeling to analyze 16 putative predictor variables for MAP occurrence in Egyptian mongooses.
Main Results:
- MAP DNA detected in 7.43% of surveyed carnivores.
- Highest prevalence in red fox (10%) and Egyptian mongoose (6%).
- First report of MAP occurrence in common genet.
- MAP DNA in feces suggests subclinical shedding.
- Mongoose MAP probability linked to higher altitude, temperature stability, and lower rainfall; livestock farm density was not significant.
Conclusions:
- Carnivores, including stone martens and common genets, are exposed to MAP.
- Subclinical carriers may contribute to environmental contamination and transmission.
- Environmental factors, not livestock proximity, appear to drive MAP infection in Egyptian mongooses.
- Further research, including MAP isolation, is needed to confirm presence in wildlife populations.
