Dalgliesh R J, Stewart N P, Duncalfe F
Z Parasitenkd. 1981;64(3):347-51. doi: 10.1007/BF00927381.
Two strains of Babesia bovis that had been serially blood passaged in splenectomized calves 27 to 33 times, a procedure known to have reduced their virulence for normal cattle, were shown to have low pathogenicity for replete, female Boophilus microplus. In comparison with a strain of B. bovis unmodified by repeated blood passage, the two modified strains infected higher proportions of ticks and produced comparable numbers of morphologically similar parasites in their haemolymph, but killed significantly fewer of them. Red discolouration of haemolymph was observed in many ticks infected with the unmodified strain, but in none of those infected with the modified strains. It is suggested that the modified strains have lost a quality causing pathological effects on the gut cells of infected ticks.
两株经脾切除的小牛连续传代27至33次的牛巴贝斯虫，这一过程已知会降低它们对正常牛的毒力，结果显示其对饱血的微小牛蜱雌蜱致病性较低。与一株未经反复传代修饰的牛巴贝斯虫相比，这两株修饰菌株感染蜱的比例更高，并且在其血淋巴中产生了数量相当、形态相似的寄生虫，但杀死的蜱明显更少。在许多感染未修饰菌株的蜱中观察到血淋巴发红，但感染修饰菌株的蜱中均未出现这种情况。有人认为，修饰后的菌株已失去了对受感染蜱肠道细胞产生病理影响的某种特性。
