Seasonal dynamics of Rhipicephalus rossicus attacking domestic dogs from the steppic region of southeastern Romania

Background: Danube Delta Biosphere Reserve is one of the most interesting regions in Europe from an epidemiological point of view due to its great biodiversity, local climatic conditions and various types of habitats. Moreover, there is no data regarding the ectoparasite communities of dogs from this area. In this frame, the aims of our study were to establish the tick communities parasitizing dogs and to provide new data regarding seasonal dynamics of a neglected tick species, Rhipicephalus rossicus. Methods: A survey was carried out in order to gather information regarding tick species attaching to domestic dogs from a steppic region of southeastern Romania and to establish their seasonal dynamics. The research was conducted from 1 December 2012 to 30 November 2013, on 8 dogs from Iazurile, a locality from the west-central part of the Danube Delta Biosphere Reserve. In total, 384 examinations were made, each dog being checked for tick infestation 4 times per month, for one year. Results: The 893 ticks found belonged to six species: R. rossicus (95.6%), Dermacentor reticulatus (3.2%), Ixodes ricinus (0.5%), Hyalomma marginatum (0.3%), Rhipicephalus sanguineus sensu lato (s.l.) (0.2%) and Ixodes crenulatus (0.1%). From the 91 positive examinations, R. rossicus was found in 80 (87.9%). Single species infestation occurred in 84 examinations. In 7 out of 91 positive examinations mixed infestation were found. No ticks were found in December, January and September. Conclusions: For R. rossicus, high frequency and intensity were observed in May, June and July. The activity peaks for D. reticulatus were in spring and autumn. Our results highlight that within the range of R. sanguineus s.l., the most common dog tick worldwide, selected dog populations may be predominantly infested by closely related species, like in our case, R. rossicus.