Molecular Evidence of Theileria and Anaplasma Species in Hyalomma marginatum Ticks Infesting Goats in Qinghai, China

Abstract

Ticks are obligate hematophagous arthropods and important vectors of various pathogens. This study identified tick species parasitizing goats in Guide County, Qinghai Province, China, and screened for Theileria and Anaplasma species. Tick specimens were identified via morphological observation and molecular analysis of 16S rRNA and cox1 gene sequences. Pathogen detection was performed using PCR targeting the 18S rRNA gene of Theileria and the groEL gene of Anaplasma, followed by sequencing and phylogenetic analysis. Morphological and molecular data consistently identified all 80 engorged tick samples collected from goats on a single farm as Hyalomma marginatum, with 97.7–99.7% sequence similarity to reference sequences. Among the 80 tick samples, the DNA detection rate for Theileria ovis was 5.0% (4/80), 17.5% for Theileria luwenshuni (14/80), and 6.3% for Anaplasma ovis (5/80). In this study, H. marginatum was identified in Guide County, Qinghai Province, thereby enriching the current knowledge of tick species distribution in this region. Furthermore, the PCR detection of T. ovis, T. luwenshuni, and A. ovis DNA in H. marginatum provides fundamental molecular surveillance data for tick-borne pathogen monitoring in this region; however, because all examined ticks were engorged, the detected DNA may have originated from the residual host blood meal, and these findings do not demonstrate infection of the ticks or vector competence.