Prevalence and distribution of Babesia and Theileria species in roe deer from Spain

Abstract

Babesiosis and Theileriosis are important worldwide-distributed tick-borne diseases for human and animals. Their presence in a particular area depends on the presence of suitable tick-vector and host species as well as competent reservoirs such as roe deer, one of the most abundant wild cervids in Spain.

Spleen samples from 174 roe deer hunted in Spain were analysed to determine the prevalence of Babesia and Theileria species. DNA of both piroplasms was firstly detected using a commercial qPCR. Then, positive samples were molecularly characterized at the 18S rRNA and ITS1 genes of Babesia spp. and Theileria spp. The possible influence of some factors such as ecological area, age and sex was also assessed.

Overall, 89.7% of roe deer were positive to any of the two piroplasms. Theileria spp. was more prevalent (60.9%) than Babesia spp. (19.0%); species identification could not be achieved in 17.3% of positive samples. Babesia prevalence was significantly higher in young animals and in roe deer from Oceanic regions, in contrast to Theileria spp. Five species were identified: Theileria sp. OT3 (60.3%), Babesia capreoli (15.5%), Babesia venatorum (2.9%), Theileria sp. 3185/02 (0.6%) and Babesia bigemina (0.6%). The coinfection B. capreoli/T. sp. OT3 was the most common (4.6%) followed by B. venatorum/T. sp. OT3 (0.6%) and B. bigemina/T. sp. OT3 (0.6%).

Our results reveal that Theileria spp. and Babesia spp. are prevalent piroplasms in roe deer from Spain. These cervids can act as reservoirs for several Babesia and Theileria species, including the zoonotic B. venatorum. This study represents the first description of B. venatorum and B. bigemina in roe deer from Spain.