Department of Parasitology, Faculty of Veterinary Medicine, Matrouh University, Matrouh, Egypt.
Department of Biochemistry, Faculty of Veterinary Medicine, Matrouh University, Matrouh, Egypt.
BMC Vet Res. 2023 Aug 31;19(1):138. doi: 10.1186/s12917-023-03702-4.
Tick-borne blood pathogens cause highly pathogenic diseases, which are associated with substantial economic losses in ruminants. Despite this, epidemiological research on these pathogens remains neglected in many countries. This study initiated a regional epidemiological survey that included the detection of molecular prevalence, associated risk factors, and gene sequencing, combined with phylogenetic analysis, targeting the two main tick-borne blood protozoan and rickettsial pathogens of Babesia, Theileria, and Anaplasma that infect small ruminants. One hundred blood samples were collected from 76 sheep and 24 goats.
Microscopic examination of Giemsa-stained blood films revealed that 73% of the samples were infected with at least one species of the three blood pathogenic organisms. Molecular diagnosis based on the 18 S rRNA for Babesia and Theileria species and the major surface protein 4 (msp4) for Anaplasma species, revealed that 43% of the small ruminants were infected with at least one of these pathogens. The animal's sex was the most significant associated risk factor, with 49.4% of female animals infected compared with only 4% of male animals (P < 0.05). The open breeding system recorded the highest infection rate for tick-borne blood pathogens. Homology-based and phylogenetic analyses indicated that the specific isolate species were Babesia ovis (B. ovis), Theileria ovis (T. ovis), and Anaplasma ovis (A. ovis), with sequences showing significant identities with isolates from sheep, goats, and other animal species, and geographically diverse countries in Africa, Asia, and Europe, in addition to Egypt.
This was the first molecular evidence of B. ovis, T. ovis, and A. ovis infections in sheep and goat populations in the North Coast region of Egypt. More extensive studies are required to develop an epidemiological map of blood pathogenic organisms, while more effective control strategies are required to reduce the burden of tick-borne pathogens on small ruminants.
蜱传血液病原体可引起高致病性疾病，给反刍动物造成了巨大的经济损失。尽管如此，这些病原体的流行病学研究在许多国家仍未得到重视。本研究开展了一项区域性流行病学调查，包括分子流行率检测、相关危险因素调查以及基因测序，并结合系统发生分析，对感染小反刍动物的两种主要蜱传血液原生动物和立克次体病原体巴贝虫、泰勒虫和无形体进行了研究。共采集了 76 只绵羊和 24 只山羊的 100 份血液样本。
吉姆萨染色血片的显微镜检查显示，73%的样本至少感染了三种血液病原体中的一种。基于巴贝斯虫和泰勒虫的 18S rRNA 和无形体的主要表面蛋白 4（msp4）的分子诊断显示，43%的小反刍动物感染了这些病原体中的至少一种。动物的性别是最重要的相关危险因素，感染的雌性动物占 49.4%，而雄性动物仅占 4%（P<0.05）。开放的繁殖系统记录到了蜱传血液病原体的最高感染率。基于同源性和系统发生分析表明，特定的分离株种类为绵羊巴贝斯虫（B. ovis）、绵羊泰勒虫（T. ovis）和绵羊无形体（A. ovis），序列与来自绵羊、山羊和其他动物物种以及非洲、亚洲和欧洲不同国家的分离株具有显著的同源性。
这是在埃及北部沿海地区的绵羊和山羊群体中首次发现绵羊巴贝斯虫、绵羊泰勒虫和绵羊无形体感染的分子证据。需要开展更广泛的研究来绘制血液病原体的流行病学图谱，同时需要制定更有效的控制策略来减轻蜱传病原体对小反刍动物的负担。
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