Sarcoptic Mange in Wild Foxes from Central Chile: Fine-Scale Assessment of a Global Disease.

Abstract

Sarcoptic mange (SM), caused by the mite Sarcoptes scabiei, is a globally distributed disease affecting a broad range of hosts and posing a potential threat to wildlife. However, its full ecologic impact remains unclear. This study investigates SM occurrence in two native fox species (Lycalopex spp.) in rural central Chile, exploring its association with macrohabitat types, land covers, domestic dogs, and human presence. Fieldwork was conducted across three rural sites (<56 km apart), representing distinct macrohabitats: exotic monoculture tree plantations (Alto Colorado) and two native Mediterranean coastal forest sites, La Estrella (thorn shrubland) and Callihue (sclerophyllous forest). At each site, 10 camera traps were deployed within 100-ha grids for 13 mo. Foxes were detected in all stations, and individuals showing lesions consistent with SM (SM-foxes) were found in 24 of 30 stations, accounting for 329 of 3,140 fox images (10.4% observed prevalence). Domestic dogs were recorded at 28 stations, detected up to 7.9 km from human settlements. In our fine-scale approach, foxes, SM-foxes, and dogs were present across all macrohabitats and land covers, tending to be more abundant in native landscapes. The occurrence of SM was weakly associated with human presence and, to a lesser extent, with domestic dogs, that latter of which nonetheless remain the most plausible original source of SM in the region. In general, SM occurrence, foxes, and domestic dogs were more frequent closer to human settlements and farther from urban areas, reflecting a complex association with human presence. Human settlements were not consistently related to altered macrohabitats such as exotic plantations. Sarcoptes scabiei circulation is probably maintained through both direct and indirect contact, involving occasional spillover from dogs, prey, and infected carcasses. These findings underscore the importance of rural areas as hotspots for dogs-fox interactions and highlight the importance of understanding fine-scale pathogen dynamics for wildlife conservation.