Population Genetic Analysis of Theileria annulata from Six Geographical Regions in China, Determined on the Basis of Micro- and Mini-satellite Markers.

Fangyuan Yin,Guangyuan Liu,Diaeldin A Salih,Zhijie Liu,Guiquan Guan,Junlong Liu,Youquan Li,Hong Yin,Aihong Liu,Jianxun Luo

doi:10.3389/fgene.2018.00050

Fangyuan Yin, Guangyuan Liu + Show 8 more

Open Access

https://doi.org/10.3389/fgene.2018.00050

Copy DOI

Abstract

Theileria annulata, a tick-borne apicomplexan protozoan, causes a lymphoproliferative disease of cattle with high prevalence in tropical and sub-tropical regions. Understanding the genetic diversity and structure of local populations will provide more fundamental knowledge for the population genetics and epidemics of protozoa. In this study, 78 samples of T. annulata collected from cattle/yaks representing 6 different geographic populations in China were genotyped using eight micro- and mini-satellite markers. High genetic variation within population, moderate genetic differentiation, and high level of diversity co-occurring with significant linkage disequilibrium were observed, which indicates there is gene flow between these populations in spite of the existence of reproductive and geographical barriers among populations. Furthermore, some degree of genetic differentiation was also found between samples from China and Oman. These findings provide a first glimpse of the genetic diversity of the T. annulata populations in China, and might contribute to the knowledge of distribution, dynamics, and epidemiology of T. annulata populations and optimize the management strategies for control.

Highlights

Tropical theileriosis, one of the fatal tick-borne diseases, caused by Theileria annulata is transmitted by ticks of the genus Hyalomma and widespread in North Africa, southern Europe, India, the Middle East and Central Asia (Robinson, 1982)
Sporozoites are inoculated into the host by feeding ticks and rapidly invade leukocytes, Population Genetic Analysis of Theileria annulata transformed into multinucleated schizonts that rupture and release un-nucleate schizoites
The population genetic characteristics analysis revealed that Xinjiang population showed more diversity than other populations of T. annulata

Summary

Introduction

One of the fatal tick-borne diseases, caused by Theileria annulata is transmitted by ticks of the genus Hyalomma and widespread in North Africa, southern Europe, India, the Middle East and Central Asia (Robinson, 1982). T. annulata infection can occur in a carrier state during theileriosis recovery, which leads to continual spreading of the diseases (Bishop et al, 2004). This parasite has a complex life cycle undergoing two phases, haploid asexual propagation in bovine hosts and diploid sexual generation in ticks (Gauer et al, 1995). Sporozoites are inoculated into the host by feeding ticks and rapidly invade leukocytes, Population Genetic Analysis of Theileria annulata transformed into multinucleated schizonts that rupture and release un-nucleate schizoites. The ingested piroplasms from infected bovines by ticks survive in the gut where male and female gametes occur fusing to form zygotes and differentiate into motile kinetes. The infections of T. annulata were detected from non-epizootic areas, Guangdong, Chongqing, Hunan, Yunnan, and Guizhou (Yin et al, 2008; Liu et al, 2015; Abdallah et al, 2017)

Methods

Results

Discussion

Conclusion