Anderson M L, Reynolds J P, Rowe J D, Sverlow K W, Packham A E, Barr B C, Conrad P A
California Veterinary Diagnostic Laboratory, School of Veterinary Medicine, University of California, Davis 95617-1770, USA.
J Am Vet Med Assoc. 1997 Apr 15;210(8):1169-72.
To determine whether heifers with naturally acquired congenital exposure to Neospora sp would transmit the infection to their offspring during gestation.
Prospective cohort study.
Neonatal heifers on a dairy with a history of Neospora sp infections were selected for the study on the basis of their serum titers to Neospora sp, as determined by the use of indirect fluorescent antibody testing. Seropositive heifers (n = 25) had titers > or = 1:5,120 and seronegative heifers (25) had titers < or = 1:80. All heifers were raised and bred on the dairy, and samples were obtained from heifers and their calves at the time of calving.
Blood samples were tested for Neospora sp antibodies. Histologic evaluations, Neospora sp immunohistochemical examinations, and protozoal culturing were performed on samples obtained from selected offspring (second-generation calves).
Seropositive heifers gave birth to calves with titers > or = 1:1,280 to Neospora sp. All offspring from seropositive heifers that were necropsied had evidence of Neospora sp infection. All seronegative heifers and their offspring had titers < 1:80 to Neospora sp.
Congenitally acquired Neospora sp infection can persist in clinically normal heifers and be transmitted transplacentally to their offspring. Vertical transmission can be a way by which neosporosis is maintained in herds.
确定自然获得先天性新孢子虫感染的小母牛在妊娠期是否会将感染传播给其后代。
前瞻性队列研究。
选择一家有新孢子虫感染病史的奶牛场的新生小母牛进行研究，根据间接荧光抗体检测确定的血清滴度来选择。血清阳性小母牛（n = 25）滴度≥1:5,120，血清阴性小母牛（25头）滴度≤1:80。所有小母牛在奶牛场饲养和繁殖，产犊时从小母牛及其犊牛采集样本。
检测血样中的新孢子虫抗体。对从选定后代（第二代犊牛）采集的样本进行组织学评估、新孢子虫免疫组化检查和原虫培养。
血清阳性小母牛所生犊牛对新孢子虫的滴度≥1:1,280。所有经尸检的血清阳性小母牛的后代都有新孢子虫感染的证据。所有血清阴性小母牛及其后代对新孢子虫的滴度均<1:80。
先天性获得的新孢子虫感染可在临床正常的小母牛中持续存在，并经胎盘传播给其后代。垂直传播可能是新孢子虫病在牛群中持续存在的一种方式。
