Babesia and Theileria Identification in Adult Ixodid Ticks from Tapada Nature Reserve, Portugal

This study, conducted in a nature reserve in southern Portugal, investigated the frequency and diversity of tick-borne piroplasms in six species of adult ixodid ticks removed from 71 fallow deer (Dama dama) and 12 red deer (Cervus elaphus), collected over the period 2012-2019. The majority of 520 ticks were Ixodes ricinuc (78.5%), followed by Rhipicephalus sanguineus sensu lato, Hyalomma lusitanicum, Haemaphysalis, punctata, Dermacentor marginatus, and Ixodes hexagonus. The R. sanguineus ticks collected from the deer were clearly exophilic, in contrast to the endophilic species usually associated with dogs. Four tick-borne piroplasms, including Theileria spp., and the zoonotic species, Babesia divergens and Babesia microti, were detected. B. divergens 18S rDNA, identical to that of the bovine reference strain U16370 and to certain strains from red deer, was detected in I. ricinus ticks removed from fallow deer. The sporadic detection of infections in ticks removed from the same individual hosts suggests that the piroplasms were present in the ticks rather than the hosts. Theileria sp. OT3 was found in I. ricinus and, along with T. capreoli, was also detected in some of the other tick species. The natural vector and pathogenic significance of this piroplasm are unknown.

Automated summary

This study investigated the frequency and diversity of tick-borne piroplasms in six species of adult ixodid ticks removed from fallow deer and red deer in a nature reserve in southern Portugal. Four tick-borne piroplasms, including zoonotic pathogens, were detected. The study also found sporadic infections in ticks removed from the same individual hosts, suggesting the presence of piroplasms in ticks rather than the hosts.