Epizootiology and pathology of sarcoptic mange in two species of fox in human-dominated landscapes of Chile

Abstract

Sarcoptic mange is a disease caused by Sarcoptes scabiei with catastrophicconsequences for wildlife. We inspected for mange 122 Andean foxes (Lycalopexculpaeus), sampled by active (n=66) or passive (n=56) surveillance, and 28 SouthAmerican grey foxes (L. griseus; all passively obtained) in Chile, 2015-2019. In Andeanfoxes, gross lesions of mange were diagnosed in 24% of passively and 9% of activelysampled foxes, although observed prevalences might be underestimated.Seroprevalence was 37% and 18%, respectively, indicating that some individualsrecovered from infection or were developing the disease. No differences were foundbetween age and sex groups. Comparing passively sampled animals only, mange wassignificantly less prevalent in grey foxes (5%). Body condition was significantly better inAndean foxes without lesions than in diseased foxes, which had significantly loweralbumin concentrations than healthy individuals. Diseased foxes had slightly higherplatelet counts. Among the 12 foxes with gross lesions, four individuals werecategorized as having type I, six individuals as type II, and two foxes as type III lesions,based on clinical severity. Severity of correlated with gross lesions and includedirregular epidermal hyperplasia with hyperkeratosis which was marked in type II and IIIinfections. Conventional PCR targeting a of the cox1 gene fragment revealed fournucleotide sequence types, showing 98.5-99.7% identity among them and between99.4-100% with previously published sequences of Sarcoptes scabiei. A significantassociation between the occurrence of mange in foxes and distance to the nearesthouse was found. We speculate that diseased foxes tended to approach humansettlements, perhaps in search of food. The visual inspection of more than 200 ruraldogs from the study area did not reveal gross mange lesions in any animal. Sarcopticmange is enzootic in the Andean fox in the study area and should be considered in themanagement of the species.