Use of Remote Cameras to Monitor the Potential Prevalence of Sarcoptic Mange in Southern Texas, USA

Abstract

Sarcoptic mange, caused by the mite Sarcoptes scabiei , is a common, highly contagious skin disease that has been reported from more than 100 species of mammals, including humans. Our objectives were to 1) determine the prevalence of sarcoptic mange within mammals from southern Texas, and 2) determine the efficacy of using remote cameras to estimate mange prevalence. We collected remote camera photographs from a 64-km area and blood and skin scrapings from 166 mammals representing 12 species in southern Texas, US during 2012-13. Only 16% of the 344,395 photograph series were of animals with an appearance consistent with sarcoptic mange and only individuals of four species: 16/25 feral hogs ( Sus scrofa ), 13/28 white-tailed deer ( Odocoileus virginianus ), 18/25 coyotes ( Canis latrans ), and 1/5 nilgai ( Boselaphus tragocamelus ) displayed alopecia, seborrhea, and crusted lesions that were consistent with mange. However, only feral hogs, coyotes, and white-tailed deer had mites present within skin scrapings. Two photographs of each collected mammal that displayed characteristics consistent with mange (n=83 animals; 166 photographs) were reviewed in a blind trial by a veterinarian experienced with cases of mange. The veterinarian correctly identified 18 and 97 animals from photographs as positive and negative for mange, respectively, with 19, 9, and 23 animals from photographs being false positive, false negative, and inconclusive, respectively. Moderate to severe cases of mange were readily identifiable via photographs; however, mild cases and summer coats often were misdiagnosed, making the technique of debatable use.

A review of sarcoptic mange in North American wildlife

“…This technique has become popular because it likely reduces the bias of clinically-ill animals being more likely to be shot or caught (Carricondo-Sanchez et al, 2017). Camera traps have been used to estimate prevalence of sarcoptic mange in coyotes ( Canis latrans ), feral swine, and white-tailed deer ( Odocoileus virginianus ), but only severe cases of mange were consistently diagnosed, and mild cases often went undetected (Brewster et al, 2017). Camera traps have also been used to monitor mange in raccoon dogs in Japan, wolves ( Canis lupus ) in Italy and Spain, and bare-nosed wombats ( Vombatus ursinus ) in Australia (Oleaga et al, 2011; Borchard et al, 2012; Galaverni et al, 2012; Saito and Sonoda, 2017).…”

“…In North America, populations of red foxes, coyotes, and gray wolves appear to experience epizootics every thirty to forty-five years (Pence and Windberg, 1994). Mild cases of mange have been recently reported in Texas in white-tailed deer but are presumed to not be contributing to morbidity or mortality (Brewster et al, 2017). There are several examples of sarcoptic mange in novel hosts in the North America.…”

Biology and management of sarcoptic mange in wild Caprinae populations

“…Camera trapping, widely used for wildlife research, conservation, and documentation purposes worldwide, has proved useful for mange surveillance in the wolf Canis lupus (Oleaga et al 2011), red fox Vulpes vulpes (Carricondo‐Sánchez et al 2017), coyote Canis latrans (Brewster et al 2017), racoon dog Nyctereutes procyonoides (Saito & Sonoda 2017), wild boar Sus scrofa (Haas et al 2015), white‐tailed deer Odocoileus virginianus , and nilgai Boselaphus tragocamelus (Brewster et al 2017).…”

“…Moderate‐to‐severe cases of mange are readily identifiable in photographs and videos; however, seasonal changes in coat patterns (e.g. moult) may confound diagnostics (Brewster et al 2017).…”

Spatiotemporal spread of sarcoptic mange in the red fox (Vulpes vulpes) in Switzerland over more than 60 years: lessons learnt from comparative analysis of multiple surveillance tools

“…Nevertheless, the strength of such surveys is that they are cheap, applicable to the whole country and easily repeatable. Although camera-trapping has already been used to detect MLL occurrence in wildlife [19, 110, 111], this is the first long-term assessment (15 years) of mange occurrence using bycatch camera-trap pictures collected during repetitive sessions in selected sectors. This constancy allowed estimating MLL prevalence and its temporal trend.…”