STUDIES ON SUSCEPTIBILITIES OF BLACKFLIES TO INFECTIONS WITH THREE SPECIES OF BOVINE ONCHOCERCA

在大分、熊本和其他五个地方的牛舍进行了调查，以弄清牛嗜酸菌和库蚊对三种牛盘尾丝虫感染的敏感性或耐受性。结果表明，双齿泽兰、阿拉卡瓦、青海和大生对稻瘟病菌均表现完全感病，而大豆杉、阿拉卡瓦和九州海棠则对连片飞虱表现完全感病。只有双齿拟青霉支持牙根结线虫发育到第三阶段。相反，二齿拟单胞菌对连环拟青霉和九州单胞菌对拟单胞菌表现出不耐药特性。前者被认为干扰了连片吸虫微丝虫在胸腔内的发育，而后者被观察到不摄取微丝吸虫。虽然阿拉卡瓦库蚊有与辽宁库蚊相似的未知丝虫的第三级幼虫，但所有8种库蚊均不含牛钉螺幼虫。只有松泽线虫才能摄取钉螺微丝虫。总体而言，第一次澄清了不同种类的黑蝇对牛Onchocerca的敏感度不同。此外，在某些种类的黑蝇中，显示出不同种类的钉螺不同。

Investigations were carried out at cattle sheds in Oita, Kumamoto and five other localites to clarify susceptibility or refractoriness of boviphilic Simulium and Culicoides to infections with three bovine Onchocerca species. As a result, Simulium bidentatum, S.arakawae, S.aokii, and S.daisense showed a complete susceptibility to O.sp., whereas S.daisense, S.arakawae and S.kyushuense were susceptible to O.lienalis. Only S.bidentatum was found to support O.gutturosa development to third-stage. In contrast, refractoriness was shown in S.bidentatum against O.lienalis and in S.kyushuense against O.sp. The former blackfly species was thought to interrupt development of O.lienalis microfilariae in the thorax, whereas the latter was observed to ingest no microfilariae of O.sp. All the eight Culicoides species examined did not harbor bovine Onchocerca larvae, although C.arakawae had third-stage larvae of unknown filaria which were similar to those of O.lienalis. The Onchocercalike microfilariae were rarely ingested only by C.matsuzawai. Overall, it is clarified for the first time that the susceptibility to bovine Onchocerca differs from one blackfly species to other. Further in certain blackfly species, it is shown to differ by the species of Onchocerca.