Molecular detection of piroplasms in haematophagus flies in the Nakhon Pathom and Kanchanaburi Provinces, Thailand

Abstract

Theileria spp. and Babesia spp are tick-borne protozoan parasites that infect a wide range of domestic and wild animals. In this study, the haematophagus flies (Stomoxys and tabanids) from Kanchanaburi and Nakhon Pathom Provinces, Thailand were investigated for the presence of piroplasm DNA. All specimens were morphologically identified. The piroplasms in the insect specimens were first screened by PCR using Babesia and Theleria 18S rRNA gene and species-specific sequences based on B. bovis spherical body protein 2, B. bigemina rhoptry-associated protein 1a and Theileria spp. Sequencing was used to confirm the identity of all amplicons. In total, 68 blood sucking insects were morphologically identified as Tabanus spp. (79.41%), Stomoxys spp. (13.24%), Haematobosca spp. (5.88%) and Chrysops spp. (1.47%). PCR results showed only 2 samples were positive for Theileria spp. while all specimens were negative for Babesia spp. Based on sequence and phylogenetic analysis, Theileria spp. 18S rRNA sequences were classified into T. ovis and T. sinensis which share high identity and similarity with isolates from other countries. In this study, we describe for the first time the detection of T. sinensis in tabanid fly. We therefore recommend further investigations to confirm the biting files as a biological or mechanical vector of theses pathogens, particularly Tabanus spp, which should be regarded as a potential vector for transmission of Theileria among domestic animals in Thailand.