On the population biology of Sarcoptes scabiei infesting Iberian ibex (Capra pyrenaica)

Abstract

In this study, we analysed the Sarcoptes scabiei infrapopulations of 315 Iberian ibex (Capra pyrenaica) by means of skin digestion and differential mite counts. Mean density reached 178.2 mites/cm (range: 0.71-4514.29). Although the most frequently affected zones were hosts extremities and withers, higher mite densities were obtained from lips and extremities, suggesting that indirect infection through the substrate could also play a role in the disease epidemiology, together with direct transmission. The sex ratio of mites was female-biased (mean: 5.18 ♀♀/♂, range: 0.5-17). Larvae were more frequently found (nearly 50% of specimens) than nymphs, adult females or adult males. Mite density varied significantly between years and decreased with host age. Most of the variance was explained by the year, host sex, weight and kidney fat index (KFI). Taking into account the catabolic nature of the disease, our results suggest that hosts in good body condition could evidence a certain degree of resistance to the disease, which presumably has a genetic basis.