【摘要】 <正> 犊新蛔虫病是世界性广泛分布的一种疾病,欧洲、美洲、亚洲、澳洲和非洲各地均有发现,感染率很高,常有半数以上小牛获得感染,受害严重;在我国台湾、贵州、江西、江苏、云南、福建等地均有报告。我们在福建闽北、闽东、闽西各县检查110只小牛,感染率占52.7%。在气候寒冷的冬春季节,于饲养管理较差的情况下,常致死亡。犊新蛔虫的生活史,国外早在1922年很多兽医工作者就着手进行研究(Schwartz,1922,1925;Boulenger,1922;Griffits,1922),我国的兽医书籍和资料多采用外国的报告。犊新蛔虫的感染途径有两方面,其一是怀孕母牛吞食的侵袭性虫卵在肺中发育为第三期幼虫,以后移行至胎盘中感染小牛,产犊后20-31天发育为成虫。其次是初生的小牛于几小时内,吞食侵袭性虫卵、经43天发育为成虫(Davtyan,1935)。很多生物学和兽医工作者企图用侵袭性虫卵感染出生一日后的小牛,均未获得成功。何以出生几小时的小牛能够感染,而出生一日后就不获得感染呢?这是一个疑问。另一方面感染途径不更多还原

【Abstract】 Neoascaris vitulorum is a widespread parasites on calves in Fujian Province. According to our examintion of 110 calves we have found that their infection rate is 52.7%. The life history of N. vitulorum has been reported to pass the placenta and migrate to fetus by previous works. Many attempts to produce patent infection in adult cattle or calves more than a day old have failed; but Davtyan (1935) and Cvetkovic snd Nevenic (1960) produced patent infections by feeding embryonated eggs to calves a few hours old. In our experiment, the infection was carried on 4 calves which are borne only after a few minutes by feeding each with 20,000 N. vitulorum infective eggs. The eggs hatched in the intestine of the calves and the larvae apparently pass to the tissue and migrate into the liver and lung one day later. The 2nd stage larvae in the liver and lungs of the calves measuring 0.420-0.460×0.019- 0.021 mm in sizc. After 6 days’ growth, the larvae moult and develop into 3rd-stage attending a size of 0.540-0.580×0.022-0.026 mm; then they started to break the alveoli and migrate through the bronchioles, up the trachea and into the oesophagus, then reach the intestine, and were expelled out with the feces. The larvae of this parasite can not develop in the calves’ intestine. From this fact, we have come to the conclusion that the development of N. vitulorum must pass through the placenta of the mother cow and infection of the calf must be bone before its birth. According to Davtyan’s (1935) report after 8 hours infection, the larvae in the feces, have already attend a size of 0.60-0.67 mm long which may be mistaken. Treatment with tetramisole sulfamidini administered orally at the dose of 15 mg/kg body weight or with tabellae piperazini citratis 200-250 mg/kg is effective against N- vitulorum. We suggest that in the epidemic area of Neoascariasis, the above drug be used to treat the calves in 15-20 day after birth to expel the immature worms in intestine, so as to prevent environmental pollution and prevent pregnant the cattle from being infected by ingesting eggs.更多还原