First report of sheep naturally infected with Trypanosoma sp. in Ecuador

ABSTRACT: The prevalence of trypanosomiasis in sheep is of worldwide concern. It is a hemoparasitic disease caused by the protozoan Trypanosoma (T) spp., andthe biological cycle of transmission involves susceptible hosts and certain hematophagous flies, such as Tabanids and Stomoxys. The objective of this study was to determine the presence of Trypanosomasp. in sheep (Ovisaries). Through an applied, descriptive-prospective-cross-sectional qualitative study conducted between October 1, 2018, and January 29, 2019, blood samples extracted from the jugular vein were analyzed by the blood smear method using 2 Romanowsky staining techniques (Giemsa and Diff-Quick). Animals studied were between ages of 3 and 10 years, coming from 3 farms in the city of Colimes (Ecuador). Of 100 sampled and processed animals, 2 (2%) were positive for Trypanosoma sp., constituting the first report of this hemoparasite in sheep in Ecuador, and 1 case of Babesia spp. (1%) and 4 cases of Anaplasma marginale (4%) were also identified. However, none of these cases presented symptomatology of any hemotropic-parasitic disease. Subsequently, the positive animals were dewormed.The presence of these parasites wasconfirmedat the study site and,thus, could become a serious animal health problem.

摘要：绵羊锥虫病的流行态势备受全球学界关注。该病是由原生动物锥虫属（Trypanosoma）物种引发的血源性寄生虫病，其传播生物学循环涉及易感宿主与特定吸血昆虫类群，例如虻科昆虫（Tabanids）和厩螯蝇属（Stomoxys）昆虫。本研究旨在检测绵羊（Ovis aries）体内锥虫属未定种（Trypanosoma sp.）的感染情况。本研究于2018年10月1日至2019年1月29日开展，采用应用型描述性前瞻性横断面定性研究方案，通过血涂片法，使用两种罗曼诺夫斯基染色技术（吉姆萨（Giemsa）染色与Diff-Quick染色）对采集自颈静脉的血液样本进行分析。研究对象为3至10岁的绵羊，均来自厄瓜多尔科利姆斯市的3个养殖牧场。在100份完成采样与检测的样本中，2份（占比2%）锥虫属未定种（Trypanosoma sp.）检测结果呈阳性，这是厄瓜多尔境内绵羊感染该血源性寄生虫的首次正式报道；同时还检出1份巴贝斯虫属（Babesia spp.）阳性样本（占比1%）以及4份边缘无浆体（Anaplasma marginale）阳性样本（占比4%）。值得注意的是，所有阳性感染案例对应的受试动物均未表现出任何嗜血性寄生虫病的临床症状，研究人员随后对阳性个体实施了驱虫治疗。本研究确认了该区域存在上述寄生虫类群，因此其有可能演变为严重的动物健康隐患。