Serological survey in wild boar (Sus scrofa) in Switzerland and other European countries: Sarcoptes scabiei may be more widely distributed than previously thought

Abstract

BackgroundSarcoptic mange has recently emerged in wild boar in Switzerland, raising the question of the origin of the infection. The main aim of this study was to assess the extent of exposure of the wild boar populations to Sarcoptes scabiei in Switzerland, prior to and after the detection of mange cases, to determine whether the mite has been recently introduced into the populations concerned. We performed a serological survey using a commercially available ELISA and 1056 archived blood samples of free-ranging wild boar from Switzerland. To facilitate the interpretation of the obtained data, we additionally estimated seroprevalence in wild boar populations of four other European countries (1060 samples), both from areas with confirmed clinical cases of mange and from areas without reported cases in wild boar. Lastly, we revised the evaluation of the commercial ELISA when used with wild boar sera.ResultsSeropositive reactions were observed for samples from all five countries and from 15 of the 16 study areas. The obtained apparent seroprevalences ranged from 0.0% (0/82; 95% confidence interval [CI]: 0.0–4.4) to 17.4% (8/46; 95% CI: 7.8–31.4). Wild boar from study areas with known clinical cases and those ≤60 kg were four times more likely to be seropositive than wild boar from areas without reported cases and > 60 kg, respectively. Optical density values did not differ between the two types of study areas among seropositive samples but were significantly lower among seronegative samples from areas without than from areas with clinical cases. No difference was observed between the two sampling periods in Switzerland. The revised ELISA specificity was 96.8% (984/1017; 95% CI: 95.5–97.7) when wild boar from areas without history of mange were considered truly negative.ConclusionsSeropositivity to S. scabiei is more frequent and occurs over a larger geographic range than expected. Data suggest that the parasite is endemic within the wild boar populations of Switzerland and other European countries but that its presence is not necessarily associated with disease occurrence. Extrinsic factors which trigger disease emergence in infected populations remain to be investigated. The applied ELISA represents a promising tool for future studies.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1430-3) contains supplementary material, which is available to authorized users.

First description of sarcoptic mange in an Iberian hare (Lepus granatensis)

“…Mild infection in animals is characterized by pruritic papules, erythema, scales and alopecia, whereas the main sign in chronic cases is skin thickening due to hyperkeratosis and/or exudative crusts formation ( Rahman et al., 2010 ). In Spain, sarcoptic mange has been reported in several game species including the Iberian ibex ( Capra pyrenaica ) ( León-Vizcaíno et al., 1999 ), Southern chamois ( Rupricapra pyrenaica parva ) ( Fernández-Morán et al., 1997 ), roe deer ( Capreolus capreolus ) ( Oleaga et al., 2008a ), red deer ( Cervus elaphus ) ( Oleaga et al., 2008b ), wild boar ( Sus scrofa ) ( Haas et al., 2018 ), red fox ( Vulpes vulpes ) ( Gortázar et al, 1998 ), European wild rabbit ( Oryctolagus cuniculus ) ( Millán, 2010 ), and the introduced European mouflon ( Ovis aries musimon ), fallow deer ( Cervus dama ) and Barbary sheep ( Ammotragus lervia ) ( Iacopelli et al., 2020 ; Moroni et al., 2021 ).…”

Biology and management of sarcoptic mange in wild Caprinae populations

“…In contrast to other diagnostic methods, the detection of antibodies allows retrospective epidemiological studies on stored samples, permitting comparison within and among areas (Haas et al 2018). Immunodiagnostic methods have been a key tool in revealing the presence of Sarcoptes scabiei in hosts and zones where it was only suspected or not confirmed by mite identification (Haas et al 2018). This is particularly relevant for host species that are elusive and difficult to detect visually in the field and in host species where mange may be asymptomatic or cause only mild lesions.…”

Sarcoptic Mange of Fox Origin in Multiple Farm Animals and Scabies in Humans, Switzerland, 2018

“…We confirmed S. scabiei mite mitochondrial 16S rDNA by TaqMan real-time PCR ( 4 ) in the sampled horse, ox, goat, and fox but not in the sampled sheep, cat, dogs, or pigs. Analyses with a panel of 9 microsatellites (sarms 33, 35–38, 40, 41, 44, and 45) ( 5 ) confirmed that foxes were the source of the mites (Figure, panel F); the mites on the outbreak farm were similar to each other and to mites previously collected from foxes in Switzerland ( 6 ) but different from those collected from wild ungulates in Spain, Switzerland, France, and Italy ( 5 , 7 , 8 ).…”