Ixodid tick infections of horses, and seasonal dynamics and infection of pasture ticks with piroplasmids in Gorny Altai

Abstract

The purpose of the research is the characterization of species composition and abundance of ixodid ticks that parasitize on horses, seasonal dynamics of ticks inhabiting natural pastures and their piroplasmid infection. Materials and methods. The studies were performed in four Gorny Altai physiographic provinces. Ticks were manually collected from horses (1183 specimens). Ticks were counted on natural pastures every ten days with subsequent determination of the species composition (1109 specimens). Collected ticks of the genus Dermacentor (443 specimens) were examined by nested PCR in the presence of genus-specific primers for Babesia spp. and Theileria spp.; the species identification of discovered piroplasmas was determined by 18S rRNA gene sequencing. Results and discussion. Ixodid ticks of three genera (Dermacentor, Ixodes, Haemaphysalis) and 6 species: D. nuttalli, D. silvarum, D. reticulatus, D. marginatus, H. concinna and Ix. Persulcatus, were recorded in the collections from horses and pastures. The most numerous species was D. nuttalli (56.1%), and the most common, Ix. persulcatus, that was recorded in all districts except Kosh-Agachsky in South-Eastern Altai. D. silvarum accounted for 14.9%, and other species were represented to a lesser extent. The highest species diversity, 5 species, was observed in the Northern Altai pastures and only 1 species, D. nuttalli, was recorded in the South-Eastern Altai. The seasonal dynamics of ticks in the pasture was characterized by two peaks in numbers, namely, the spring peak in the 3rd decade of April and the autumn peak in the 2nd decade of October. The spring-summer period (March-June) had 87.1% of recorded ticks, and the autumn period (September-October) had 7.2%. Three species of the examined ticks (D. silvarum, D. marginatus, D. nuttalli) were found to have DNA of three piroplasmid species (Babesia caballi, Theileria equi and Babesia sp). Piroplasmids infection rate in ticks was 2.7-25.0%, and 2.7% on average in Gorny Altai.