Abstract
Vector-borne parasitic diseases (VBPDs) are diseases that have a major impact on the health and productivity of livestock. VBPDs, including trypanosomosis, theileriosis, and anaplasmosis, are caused by blood parasites and Rickettsiales infections that can be transmitted by biting insects. The control and elimination of VBPDs is difficult and challenging. This study contributed to better understanding the impact of hematophagous insects on carrying pathogens to livestock by investigating the detection of Trypanosoma evansi, Theileria spp. and Anaplasma spp. in hematophagous insects collected from five livestock farms in Northeastern Thailand using polymerase chain reaction (PCR). The Stomoxys and Tabanus samples were collected using Nzi and Vavoua traps. Morphological and molecular identifications of hematophagous insects were performed. The Stomoxys samples were dissected into head and abdomen parts, while the Tabanus samples were dissected into head, salivary glands, and abdomen parts before DNA extraction individually. The host blood meal in the DNA of each part of the hematophagous insects was identified using PCR targeting the prepronociceptin (PNOC) gene. PCR detection of T. evansi, Theileria spp., and Anaplasma spp. were performed by targeting the ITS2, 18s rRNA, and msp4 genes, respectively. In total, 131 insect samples were collected, with Stomoxys calcitrans being the most common species at 40 (30.53%), followed by Tabanus spp. at 14 (10.69%) and the other Stomoxys spp. at 7 (5.34%), respectively. The hemoparasite detection results identified Theileria spp. in the abdomen (21.43%; 3/14) of three Tabanus samples. Neither Anaplasma spp. nor T. evansi were detected in this study. Additionally, host blood meal DNA was found in the abdomen of Stomoxys calcitrans (4.17%; 1/24) and Stomoxys spp. (20%; 1/5). For the Tabanus spp., host blood meal DNA was detected in the head (7.14%; 1/14), salivary glands (7.14%; 1/14), and abdomen (14.29%; 2/14). These results highlighted that Tabanus spp. might play an important role in Theileria transmission.