Molecular detecting of piroplasms in feeding and questing Ixodes ricinus ticks

The purpose of this study was to detect piroplasms, which are pathogens of veterinary and zoonotic importance in ticks, that were collected from ponies and field vegetation and to determine the role of Shetland ponies as potential reservoir hosts for piroplasms. A total of 1737 feeding and 371 questing Ixodes ricinus collected from horses or vegetation were tested for the presence of Babesia and Theileria DNA. Piroplasm 18S rRNA gene amplification was conducted, and the obtained amplicons were sequenced. Babesia DNA was detected in only three ticks (one tick collected from a pony and two collected from vegetation), and all of the obtained sequences had 100% similarity to B. divergens. Theileria DNA was not present in the examined ticks. Thus, the above results indicate that ponies are probably not essential hosts for the detected species of piroplasms. Piroplasm species typical for horses (Babesia caballi and Theileria equi) were not detected because I. ricinus is not their vector. The low infection rate of I. ricinus with B. divergens shows that the disease risk for the local horse population and people associated with pony horses is low, but it demonstrates their possible role as a source of human infection in northern Poland.