Sanderson M W, Gay J M, Baszler T V
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan 66506, USA.
Vet Parasitol. 2000 Jun 10;90(1-2):15-24. doi: 10.1016/s0304-4017(00)00234-x.
A Neospora caninum seroprevalence and risk factor survey of 2585 cows was conducted in 55 beef cow-calf herds located in five northwestern states of the USA. Blood samples were collected by private veterinary practitioners and management practices were surveyed using a mail questionnaire. Producers were randomly selected from those that employed these veterinarians to perform annual herd pregnancy examinations. Questions were asked about animal management, grazing and feeding, immunization and record keeping practices. Blood was collected from a systematically selected sample of cows in each herd, and age, origin, and pregnancy status were recorded. Blood samples were analyzed for antibodies against N. caninum antigen using a monoclonal antibody-based competitive inhibition (CI) ELISA. Overall seroprevalence was 24% and within herd seroprevalence ranged from 3 to 67% with a median of 19%. Within herd seroprevalence and mean inhibition percentage were different between the five states. Herds that managed their cows on range for summer grazing had lower seroprevalence than those that did not, while increased seroprevalence was associated with higher winter stocking density. Cows less than 3 years of age had higher CI ELISA inhibition percent values than cows greater than 6 years of age. No relationship was noted between serologic status and individual cow origin (purchased or raised), or pregnancy status at the time of sampling.
在美国西北部五个州的55个肉牛母牛-犊牛群中，对2585头奶牛进行了犬新孢子虫血清流行率和风险因素调查。血样由私人兽医采集，并通过邮寄问卷对管理措施进行调查。生产者是从那些聘请这些兽医进行年度牛群妊娠检查的人中随机挑选出来的。询问了有关动物管理、放牧和饲养、免疫接种及记录保存措施的问题。从每个牛群中系统选取的奶牛样本采集血液，并记录年龄、来源和妊娠状态。使用基于单克隆抗体的竞争抑制（CI）ELISA分析血样中针对犬新孢子虫抗原的抗体。总体血清流行率为24%，牛群内血清流行率在3%至67%之间，中位数为19%。五个州之间牛群内血清流行率和平均抑制百分比有所不同。夏季在牧场放牧管理奶牛的牛群血清流行率低于不放牧的牛群，而血清流行率的增加与冬季较高的饲养密度有关。小于3岁的奶牛CI ELISA抑制百分比值高于大于6岁的奶牛。未发现血清学状态与个体奶牛来源（购买或饲养）或采样时的妊娠状态之间存在关联。
