Tick infestation (Acari: Ixodidae) in roe deer (Capreolus capreolus) from northwestern Spain: population dynamics and risk stratification

Abstract

During the 2007 and 2008 hunting seasons (April-October) the skin of 367 roe deer (Capreolus capreolus L.), hunted in different preserves from Galicia (Northwestern Spain), were examined for ticks (Acari: Ixodidae). The overall prevalence of infestation by ticks was 83.1%. The predominant species was Ixodes ricinus (83.1%), whereas a single Dermacentor marginatus specimen appeared in one roe deer. All developmental stages of I. ricinus were found parasitizing roe deer, the adults being the most frequent (82.2%), followed by nymphs (45.6%) and larvae (27.2%). The mean intensity of infestation by I. ricinus was 43.2 ± 49.85; most of them were adults (30.7 ± 31.64) and in a lesser extend nymphs (16.9 ± 24.74) and larvae (10.7 ± 29.90). Ixodes ricinus was present all over the study with percentages that oscillated between 100% in spring and 57.4% in autumn. CHAID algorithm showed the sex of roe deer as the most influential factor in tick prevalence, followed by the climatic area. The different developmental stages of I. ricinus were more frequent in males than in females, and the prevalence of adults and larvae were higher in roe deer from coastal areas than in those from mountainous and central areas, whereas nymphs were more frequent in mountainous areas. Host age and density were not determinants for tick infestation. Our results confirm that roe deer are important hosts for I. ricinus in northwestern Spain, serving as a vehicle for the geographic distribution of these ticks.

Occurrence of Borrelia and Borreliella species in Ixodes ricinus collected from roe deer in northwestern Spain

“…In total, 8885 ticks were collected; all developmental stages of I. ricinus were found infesting roe deer, with adult females being the most frequent, followed by nymphs, males and larvae (Table 1); these differences were significant by a Kruskal-Wallis test ( 2 = 87 145; P < 0.001). Our results corroborate those of Vázquez et al (2011) and Pato et al (2013), who found that, in addition to adults, deer could also support a high proportion of immature stages. The median number of ticks infesting roe deer was similar in both areas (Table 1) and the differences were not significant using the Kruskal-Wallis test (P > 0.05).…”

“…Our results corroborate those of Vázquez et al . () and Pato et al . (), who found that, in addition to adults, deer could also support a high proportion of immature stages.…”

“…Indeed, several studies have shown a positive relationship between both cervid and tick populations and therefore the risk to acquire LB (Kjelland et al ., ; Sprong et al ., ). Thus, the noticeable increase of roe deer populations and their distribution detected in northwest Spain in the last decade (Vázquez et al ., ) may be related to the significant increment on the incidence of human LB in that area subsequent to 2006 (Vázquez‐López et al ., ).…”

“…Thus, wild ungulates are among the most important feeding hosts for I. ricinus in Europe. Roe deer is the most abundant cervidae in northwestern Spain (Vázquez et al, 2011;Pato et al, 2013); they are mainly parasitized by I. ricinus (Vázquez et al, 2011) and highly exposed to Borreliella spp. (syn.…”

Anaplasma phagocytophilum—a widespread multi-host pathogen with highly adaptive strategies

“…Wild ruminants such as WTD and roe deer are among the major feeding hosts for ticks in the Eastern US and Europe, respectively, and thus considered to contribute to a rapid increase in the population of ticks (Spielman et al, 1985; Vázquez et al, 2011; Medlock et al, 2013). WTD is considered one of the major reservoir hosts for an apathogenic variant (Ap-V1) of A. phagocytophilum in the Eastern US (Massung et al, 2005).…”