Tick-borne pathogens in ticks collected from dogs in the Tickbusters survey in 2013

Abstract

Ticks are of great veterinary and medical importance; they can transmit a greater variety of diseases than any other group of arthropods. In the Netherlands the pathogen causing most human disease cases is Borrelia burgdorferi s.l., but also other pathogens are present in I. ricinus ticks, like Rickettsia, Babesia and Ehrlichia species.

Over a period of 8 months in 2013 a total of 1724 ticks originating from dogs were submitted to UCTD. From these 400 ticks were selected (287 I. ricinus, 72 I. hexagonus, 40 D. reticulatus, 6 R. sanguineus, 2 R. turanicus) for pathogen screening. The ticks were screened by polymerase chain reaction (PCR) and reverse line blot (RLB) hybridization for the presence of Ehrlichia, Anaplasma, Babesia, Theileria, Borrelia and Rickettsia species.

Of the I. ricinus ticks 6.4% (18/280) was infected with Ehrlichia/Anaplasma spp., 1.8% (5/280) with Babesia spp., 1.8% (5/280) with Theileria spp., 9.6% (27/280) with Borrelia spp., and 8.9% (25/280) with Rickettsia spp. (all Rickettsia spp. were specified as R. helvetica). Of the D. reticulatus ticks 2.5% (1/40) was infected with Babesia spp. and 1.4% (1/72) of I. hexagonus ticks with B. burgdorferi sensu lato (subspecies sensu stricto).

The pathogen B. afzelii was present in 17 of the 280 I. ricinus ticks (6.1%), which is quite a high prevalence for one of the subspecies of B. burgdorferi sensu lato. It was also found that I. ricinus ticks contained T. equi (1.1%). It needs to be confirmed if I. ricinus plays a role in addition to D.reticulatus ticks as vectors of equine piroplasmosis.

It can be concluded that there are different zoonotic pathogens present in the indigenous tick population in the Netherlands. Continued surveillance is relevant in order to stay up to date on the current pathogen prevalence status and to keep track of possible exotic tick species entering into the Netherlands.