Dijkstra Th, Barkema H W, Hesselink J W, Wouda W
Animal Health Service, P.O. Box 9, 7400 AA Deventer, The Netherlands.
Vet Parasitol. 2002 Apr 30;105(2):89-98. doi: 10.1016/s0304-4017(02)00009-2.
Eight dairy herds with evidence of post-natal transmission of Neospora caninum were used to test the hypothesis of a point source exposure by a retrospective analysis of the housing and feeding of infected age-groups. The first N. caninum-associated abortion or birth of N. caninum-seropositive offspring from the post-natally infected age-group was considered as the first indication of the infection. In seven of the eight dairy herds, a point source exposure to N. caninum of the infected age-groups was found during a limited period of common housing and feeding. In all herds studied, the analysis indicated that the cattle had been infected shortly before the first abortions occurred. In all, except one herd, the post-natal infection was more directly related to housing than to feeding. Therefore, it appeared that the feed was contaminated in the feeding alley. In one herd, the total mixed ration was found to be the probable path of infection. In all farms studied, a new dog (young, adult dog or litter) had been introduced within a period of 1.5 years prior to the first indication of N. caninum infection in the cattle. As there was evidence in all herds of vertical transmission of neosporosis for years, it is hypothesized that the newly introduced dog was infected with N. caninum by materials from already infected cattle and subsequently transmitted the infection to other cattle by shedding of oocysts.
选取了8个有犬新孢子虫产后传播证据的奶牛群，通过对受感染年龄组的圈舍和饲养情况进行回顾性分析，来检验点源暴露假说。产后感染年龄组首次出现与犬新孢子虫相关的流产或犬新孢子虫血清阳性后代出生，被视为感染的首个迹象。在8个奶牛群中的7个中，发现在有限的共同圈舍和饲养期间，受感染年龄组存在犬新孢子虫的点源暴露。在所研究的所有牛群中，分析表明牛在首次流产前不久就已被感染。除一个牛群外，在所有牛群中，产后感染与圈舍的关系比与饲养的关系更直接。因此，似乎饲料在饲养通道被污染了。在一个牛群中，发现全混合日粮是可能的感染途径。在所研究的所有农场中，在牛首次出现犬新孢子虫感染迹象前的1.5年内，都引入了新狗（幼犬、成年犬或一窝幼犬）。由于所有牛群多年来都有新孢子虫垂直传播的证据，因此推测新引入的狗通过已感染牛的物质感染了犬新孢子虫，随后通过排出卵囊将感染传播给了其他牛。
