Bovine babesiosis is a tick-transmitted haemoparasitic disease caused by Babesia bovis and B. bigemina affecting cattle of tropical and subtropical regions around the world. Pathogens are transmitted by the tick vector Rhipicephalus microplus displaying a widespread distribution in northeastern Argentina. The disease is characterized by significant animal morbidity and mortality resulting in considerable economic loss. In this study, B. bovis and B. bigemina infection was investigated in a cattle herd of 150 adult bovines of pure Braford breed raised in a tick-hyperendemic field using molecular and serum antibody tests. A highly sensitive nested polymerase chain reaction (nPCR) assay targeting a species-specific region of the apocytochrome b gene resulted in direct B. bovis and B. bigemina detection in 27.3% and 54.7% of bovines, respectively. A recently developed immunochromatographic strip test (ICT) based on recombinant forms of spherical body protein 4 and the C-terminal region of rhoptry-associated protein 1 showed that 71.3% and 89.3% of bovines were seropositive for B. bovis and B. bigemina, respectively. The mixed infection rate as observed by direct (19.3%) and indirect detection (65.3%) coincided with those expected, respectively. Importantly, four months after sampling, nine bovines of the studied herd showed clinical signs of bovine babesiosis of which six animals eventually died. Microscopic detection of infected erythrocytes in Giemsa-stained blood smears confirmed B. bovis infection. Our study demonstrates that although animals showed a relatively high and very high rate of immunity against infection with B. bovis (71.3%) and B. bigemina (89.3%) parasites, respectively, clinical cases and fatalities due to the infection with B. bovis were observed. It is proposed that the most adequate control measure in the studied epidemiological situation is to vaccinate animals to prevent losses and/or an outbreak of bovine babesiosis.

中文翻译：

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在阿根廷有急性临床和致命病例的牛群中，高度灵敏的巢式PCR和快速免疫色谱法检测牛牛和巴贝斯大孢菌感染。

牛巴贝虫病是由牛传染性贝氏杆菌和双歧杆菌引起的tick传播的血寄生虫病，感染了世界各地的热带和亚热带地区的牛。滴答载体Rhipicephalus microplus传播病原体，在阿根廷东北部分布广泛。该疾病的特征在于明显的动物发病率和死亡率，导致相当大的经济损失。在这项研究中，牛和牛双歧杆菌感染是通过分子和血清抗体测试，在壁虱-高流行性田间饲养的150只纯布拉福德纯种成年牛的牛群中进行的。靶向脱辅基细胞色素b基因的物种特异性区域的高度灵敏的巢式聚合酶链反应（nPCR）检测分别在27.3％和54.7％的牛中直接检测到牛双歧杆菌和双歧双歧杆菌。最近开发的一种基于重组体球形蛋白4和rhoptry-associated蛋白1 C端区域的免疫色谱带试验（ICT）表明，牛的B. bovis和B. bigemina的血清反应呈阳性，分别为71.3％和89.3％，分别。通过直接检出（19.3％）和间接检出（65.3％）观察到的混合感染率分别与预期相符。重要的是，采样后四个月，研究牛群中有9头牛表现出牛杆状杆菌病的临床体征，其中6头动物最终死亡。在吉姆萨染色的血液涂片中镜检感染的红细胞证实了牛双歧杆菌的感染。我们的研究表明，尽管动物对牛双歧杆菌（71.3％）和双歧双歧杆菌（89.3％）的寄生虫分别具有相对较高和非常高的免疫率，观察到由于牛双歧杆菌感染引起的临床病例和死亡。建议在所研究的流行病学情况下最适当的控制措施是给动物接种疫苗，以防止损失和/或爆发牛杆状杆菌病。