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

Table 1 Study areas and results of the serosurvey. The total number of tested wild boar samples (n), total number of seropositive animals (pos), estimated seroprevalences in percent (Prev) and 95% confidence interval (CI) are given for each study area for all samples (total) and for wild boar ≤2 years old (young age class), together with the p-values of the binomial test comparing the estimated prevalence of each study area with Uppland (baseline). P-values < 0.05 are highlighted in bold. Note that although seroprevalence was found to be higher in young than adult wild boar in general, the reverse was observed in Skåne (46 youngs, 22 adults) and Södermanland (3 youngs, 26 adults). Wild boar are free-ranging in all areas but two: The National Domain of Chambord is fenced with high walls, in this area wild boar are regularly fed by game wardens, and until 2014 medicated food containing ivermectin was spread on feeding grounds; La Mandria is also delimited by physical boundaries (although occasional outbound and inbound dispersal movements of wild boar are not excluded)

Country	Study area	ID study area	Mange status^a	Total samples		Young age class only
Country	Study area	ID study area	Mange status^a	Prev in % (pos/n)	95% CI	p-value	Prev in % (pos/n)	95% CI	p-value
Switzerland	Geneva	GE	N	2.6 (10 / 389)	1.2–4.7	0.2955	3.3 (9 / 274)	1.5–6.1	0.6096
	Midlands	SP	N	0.1 (1/105)	0.0–5.2	1.0000	1.3 (1 / 77)	0.0–7.0	1.0000
	Jura 1	J1	C	12.7 (14 / 110)	7.1–20.4	0.0021	19.7 (14 / 71)	11.2–30.9	0.0150
	Jura 2	J2	N	3.4 (3 / 88)	0.7–9.6	0.2696	4.9 (3 / 61)	1.0–13.7	0.4964
	Thurgau	TG	S	1.3 (2 / 150)	0.2–4.7	0.7586	1.7 (2 / 115)	0.2–6.1	1.0000
	Ticino	TI	C	2.8 (6 / 213)	1.0–6.0	0.2823	4.0 (5 / 124)	1.3–9.2	0.5388
France	Vosges^b	1	C	14.7 (28 / 191)	10.0–20.5	0.0006	15.0 (21 / 140)	9.5–22.0	0.0378
France	Chambord^c	2	S	17.4 (8 / 46)	7.8–31.4	0.0004	21.1 (4 / 19)	6.1–45.6	0.0276
Sweden	Uppland	3	N	0.0 (0 / 82)	0.0–4.4	–	0.0 (0 / 33)	0.0–10.6	–
	Södermanland	4	C	10.3 (3 / 29)	2.2–27.4	0.0222	0.0 (0 / 3)	0.0–70.8	NA
	Skåne	5	C	10.3 (7 / 68)	4.2–20.1	0.0097	8.7 (4 / 46)	2.4–20.8	0.2231
Italy	Aosta^d	6	C	9.4 (6 / 64)	3.5–19.3	0.0159	23.8 (5 / 21)	8.2–47.2	0.0139
	Vercelli^e	7	C	6.3 (1 / 16)	0.2–30.2	0.3598	8.3 (1 / 12)	0.2–38.5	0.5936
	La Mandria^f	8	N	5.6 (10 / 179)	2.7–10.0	0.0665	5.7 (7 / 122)	2.3–11.5	0.3494
	Imperia^g	9	C	6.2 (13 / 211)	3.3–10.3	0.0473	7.6 (10 / 132)	3.7–13.5	0.2211
Spain	Barcelona	10	N	1.2 (2 / 174)	0.1–4.1	0.8306	1.5 (2 / 137)	0.2–5.2	1.0000

^aThree different mange status are considered: “non-reported” (N) in absence of known clinical cases, “confirmed” (C) if Sarcoptes scabiei was identified in skin samples from clinical cases, and “suspected” (S) if wild boar with suspicious skin lesions have occurred but the etiological role of S. scabiei was not confirmed (not investigated or not detected). In Thurgau, a few wild boar with focally extensive, well demarcated alopecia were documented by phototrapping but not submitted to veterinary examination. In the National Domain of Chambord, multiple wild boar with suspicious skin lesions were tested for mites in skin scraping material (light microscopy) or skin samples (histology, polymerase chain reaction) but S. scabiei was never found
^bParc Naturel Régional des Vosges du Nord (Vosges Department)
^cNational Domain of Chambord (Loir-et-Cher Department)
^dAosta Valley Region
^eVercelli Province (Piedmont Region)
^fParco Regionale La Mandria (Piedmont Region)
^gImperia (Liguria Region)

ISSN: 1746-6148