Smith R D, Molinar E, Larios F, Monroy J, Trigo F, Ristic M
Am J Vet Res. 1980 Dec;41(12):1957-65.
A total of 22 nonsplenectomized Hereford, Holstein-Friesian, and cross-bred 18-month-old cattle were used to assess the degree of protection conferred by previous infection with Babesia bovis or B bigemina against infection and disease from tick-borne challenge exposure with the heterologous species. Prior infection with B bigemina or B bovis did not significantly (P less than 0.05) reduce the susceptibility of cattle to tick-borne infection and disease caused by the heterologous species. Carrier infections were not activated during heterologous species challenge exposure, nor was the severity of the challenge-exposure infection aggravated. Immunologic cross reactivity in the indirect fluorescent antibody test was restricted to the period during and shortly after recovery. Homologous indirect fluorescent antibody titers persisted long after primary infections with B bovis, but gradually declined in B bigemina-immune cattle. Babesia bovis infections caused severe reactions characterized by high fever, pancytopenia, and death of 9 of 15 infected cattle. Total serum bilirubin and urea nitrogen values increased markedly within 24 hours preceding death and were often accompanied by clinical signs of CNS involvement (incoordination, opisthotonos, and paddling). Microscopic lesions were restricted largely to kidney, CNS, and liver parenchyma and were characterized by vascular congestion and aggregation of infected erythrocytes in small vessels. Babesia bigemina, in contrast, caused only mild fever and anemia despite prolonged parasitemia and marked thrombocytopenia. The absence of significant (P less than 0.05) heterologous species immunity indicated that protection of cattle from these 2 babesial parasites will require specific immunization against each species.
总共使用了22头未进行脾切除的18月龄赫里福德牛、荷斯坦 - 弗里生牛及其杂交牛，以评估先前感染牛巴贝斯虫或双芽巴贝斯虫对蜱传播的异源物种感染和疾病所提供的保护程度。先前感染双芽巴贝斯虫或牛巴贝斯虫并未显著（P小于0.05）降低牛对蜱传播的异源物种感染和疾病的易感性。在异源物种攻击暴露期间，带虫感染未被激活，攻击暴露感染的严重程度也未加重。间接荧光抗体试验中的免疫交叉反应仅限于恢复期间及恢复后不久。同源间接荧光抗体滴度在初次感染牛巴贝斯虫后持续很长时间，但在双芽巴贝斯虫免疫的牛中逐渐下降。牛巴贝斯虫感染引起严重反应，表现为高热、全血细胞减少，15头感染牛中有9头死亡。在死亡前24小时内，总血清胆红素和尿素氮值显著升高，且常伴有中枢神经系统受累的临床症状（共济失调､角弓反张和划水）。显微镜下病变主要局限于肾脏、中枢神经系统和肝实质，其特征为血管充血和小血管内感染红细胞聚集。相比之下，尽管双芽巴贝斯虫血症持续时间长且血小板显著减少，但仅引起轻度发热和贫血。缺乏显著（P小于0.05）的异源物种免疫力表明，要保护牛免受这两种巴贝斯虫寄生虫的侵害，需要针对每种物种进行特异性免疫接种。
