Lack of evidence of paratuberculosis in wild canids from south-western Europe

Wild carnivores are at the top of the trophic chain.
They are predators and carrion consumers, and thus, prone to
come in contact with disease agents contaminating the
environment or infecting live or dead animals. We hypothesized
that wild canids could be used as sentinels for the
detection of regions with higher Mycobacterium avium paratuberculosis
(MAP) prevalence in wild and domestic animals.
To test this hypothesis, we set up an ELISA to test 262 wolf
(Canis lupus) and fox (Vulpes vulpes) sera for MAP-specific
antibodies and processed a subset of samples for culture (n=
61), MAP-specific PCR (15) and histopathology (14). In
wolves, the optical density (OD) values in the ELISA were
continuously distributed. Ten fox sera (4%) had OD readings
of over twice the mean, suggesting contact with mycobacteria.
However, all samples tested by PCR were negative for
both IS900 and ISMAP02 sequences, and samples cultured
for MAP yielded no growth. No visible paratuberculosis or
tuberculosis-compatible lesions were recorded. On histopathological
examination, no lesions compatible with mycobacterial
diseases were observed. These results suggest that wild
canids show little or no evidence of paratuberculosis and are
unlikely to be useful sentinels for the detection of MAP in
Southwestern Europe.