Genetic epidemiology of Sarcoptes scabiei in the Iberian wolf in Asturias, Spain.

BACKGROUND: During the last decades, attempts have been made to understand the molecular epidemiology of Sarcoptes scabiei, and to detect and clarify the differences between isolates from different hosts and geographic regions. Two main phenomena have been described: (i) host-taxon derived-Sarcoptes mite infection in European wild animals (revealing the presence of three separate clusters, namely herbivore-, carnivore- and omnivore-derived Sarcoptes populations in Europe) and (ii) prey-to-predator Sarcoptes mite infection in the Masai Mara ecosystem.
RESULTS: Using one multiplex of 9 microsatellite markers and Sarcoptes mite samples from sympatric Pyrenean chamois, red deer, red fox and Iberian wolf, different population structure analyses revealed concordance with the host-taxon law described for wild animals in Europe, with two main host-derived Sarcoptes mite populations, herbivore- and carnivore-derived. Surprisingly, Iberian wolf derived Sarcoptes populations had the highest genetic diversity among the other populations, including two different subpopulations: one similar to the herbivore-derived Sarcoptes populations, and another similar to carnivore (fox)-derived Sarcoptes mite population.
CONCLUSIONS: The host-taxon effect in wild animals is still supported with the maintenance of carnivore- and herbivore-derived Sarcoptes clusters' separation in analyzed mites. However, this phenomenon could be modified with the inclusion of a large predator as wolf in the present work, revealing prey-to-predator Sarcoptes mite infection between the studied host-taxa and suggesting the importance of wolf's immune system for explaining the high variability reported in C. lupus derived mites. Further studies of host diet, behavior and movement, and regarding the role played by its immune system, would be of great help to clarify interactions between the two hypotheses, host-taxon and prey-to-predator.