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

Abstract

Background Sarcoptic mange is a contagious skin disease of wild and domestic mammals caused by the mite Sarcoptes scabiei. Reports of sarcoptic mange in wildlife increased worldwide in the second half of the 20th century, especially since the 1990s. The aim of this study was to provide new insights into the epidemiology of mange by (i) documenting the emergence of sarcoptic mange in the red fox (Vulpes vulpes) in the last decades in Switzerland; and (ii) describing its spatiotemporal spread combining data obtained through different surveillance methods. Methods Retrospective analysis of archived material together with prospective data collection delivered a large dataset from the 19th century to 2018. Methods included: (i) a review of historical literature; (ii) screening of necropsy reports from general health surveillance (1958–2018); (iii) screening of data on mange (1968–1992) collected during the sylvatic rabies eradication campaign; (iv) a questionnaire survey (<1980–2017) and (v) evaluation of camera-trap bycatch data (2005–2018). Results Sarcoptic mange in red foxes was reported as early as 1835 in Switzerland. The first case diagnosed in the framework of the general health surveillance was in 1959. Prior to 1980, sarcoptic mange occurred in non-adjacent surveillance districts scattered all over the country. During the period of the rabies epidemic (1970s-early 1990s), the percentage of foxes tested for rabies with sarcoptic mange significantly decreased in subregions with rabies, whereas it remained high in the few rabies-free subregions. Sarcoptic mange re-emerged in the mid-1990s and continuously spread during the 2000–2010s, to finally extend to the whole country in 2017. The yearly prevalence of mange in foxes estimated by camera-trapping ranged from 0.1–12%. Conclusions Sarcoptic mange has likely been endemic in Switzerland as well as in other European countries at least since the mid-19th century. The rabies epidemics seem to have influenced the pattern of spread of mange in several locations, revealing an interesting example of disease interaction in free-ranging wildlife populations. The combination of multiple surveillance tools to study the long-term dynamics of sarcoptic mange in red foxes in Switzerland proved to be a successful strategy, which underlined the usefulness of questionnaire surveys.

Volatile scent chemicals in the urine of the red fox, Vulpes vulpes

“…Unlike acetophenone, for nearly every other compound found the median was closer to the minimum than the maximum value, indicating that for most compounds there were only a few foxes in which there was a high relative abundance. Sulfur compounds were the most significant findings in fox urine, accounting for 32% (17/ 53) of the endogenous scent compounds, and including the second most frequently found compound, 3-isopentenyl methyl sulfide (20), present in 14/15 foxes. Five sulfur compounds have only been found in foxes: 3-isopentenyl thiol (15), octanethiol (39), benzyl methyl sulfide 1.…”

“…Five others have only been reported in one or two other species: methanethiol (1, mouse and human), S-methylthioacetate (10, lion and mink), 1-phenylethane thiol (38, striped skunk), 2-phenylethane thiol (44, hooded and spotted skunk) and dimethyl tetrasulfide (47, human). Isopentyl methyl sulfide (17) has only been found in canids, 3-isopentenyl methyl sulfide (20) in canids and mink, and dimethyltrisulfide (24) in canids and humans.…”

“…They are a major cause of wildlife decline [ 1 ], and their great mobility leads to seed dispersal, often of pest species [ 17 , 18 ]. Foxes are vectors for many zoonoses, including rabies, nematodes, and mites [ 19 , 20 ]. When they become accustomed to humans, other nuisance behaviour such as bin-raiding and biting can occur [ 2 ].…”

Clinical, Parasitological, and Serological Follow-Up of Dogs with Sarcoptic Mange Treated Orally with Lotilaner

“…The clinical signs, in this cohort of dogs affected by sarcoptic mange, were compatible with those described in the literature [ 1 , 13 – 17 ]. It is likely that direct contact with the deceased red fox had initiated the process as S. scabiei are endemic in red foxes in Europe and can act as a source of infestation for domestic animals [ 18 , 19 ]. The highly contagious aspect of the disease was clearly apparent with all the animals progressively and rapidly becoming affected, as well as the transmission to humans with the development of transient cutaneous signs on the owner [ 1 , 20 ].…”

Understanding potential implications for non-trophic parasite transmission based on vertebrate behavior at mesocarnivore carcass sites

“…Among the non-trophically transmitted pathogens that cause the greatest impact on wildlife is the mite Sarcoptes scabiei , an obligate permanent parasite that causes sarcoptic mange (Niedringhaus et al 2019 ). This multi-host ectoparasite is widely distributed and affects a broad range of mammals, including ungulates and carnivores (Carricondo-Sánchez et al 2017 ; Pisano et al 2019 ; Turchetto et al 2020 ). These mites live in the epidermis of their hosts, and can be transmitted through direct contact between animals or indirectly when a susceptible host acquires free mites that have shed the skin of an infected animal, especially in dens and other sheltered sites where S. scabiei may survive for several days (Pence and Ueckerman 2002 ).…”