Yao L, Yang N, Liu Q, Wang M, Zhang W, Qian W F, Hu Y F, Ding J
Key Laboratory of Zoonosis of Ministry of Agriculture and National animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Parasitology. 2009 Sep;136(11):1251-6. doi: 10.1017/S0031182009990813. Epub 2009 Aug 7.
Neospora caninum infection is a significant cause of abortion in cattle. We investigated the tissue distribution of N. caninum in aborted bovine fetuses and dam blood samples by a nested PCR assay, and compared the nested PCR with ELISA in the diagnosis of N. caninum infection. In total, 26 aborted fetuses and 813 blood samples were collected from 8 dairy herds in Beijing (n=212) and Tianjin (n=601), China. Fifteen fetuses (57.7%) were tested N. caninum-positive by the nested PCR. N. caninum DNA was detected from the brain of 52%, kidneys of 22%, skeletal muscle of 18%, and heart of 4% of the aborted fetuses. The PCR-positive cases (55%, 11/20) were higher than seropositive cows (40%, 8/20) in a subset of 20 fetuses, but the PCR results of blood samples of the 20 cows were all negative. The seroprevalence of the 813 samples was 15.5% (43.4% of samples from Beijing, 5.7% of samples from Tianjin), compared to the PCR-positive blood samples of 0.9%. Our study showed that the nested PCR is a valuable diagnostic tool for the primary diagnosis of N. caninum in aborted fetuses, while ELISA is the preferred assay for testing blood samples collected from cows. The two assays are complementary in determining whether abortions are associated with N. caninum infection in cattle.
犬新孢子虫感染是牛流产的一个重要原因。我们通过巢式PCR检测法研究了犬新孢子虫在流产牛胎儿和母体血液样本中的组织分布，并在犬新孢子虫感染诊断中将巢式PCR与酶联免疫吸附测定（ELISA）进行了比较。总共从中国北京（n = 212）和天津（n = 601）的8个奶牛场收集了26个流产胎儿和813份血液样本。通过巢式PCR检测，15个胎儿（57.7%）被检测为犬新孢子虫阳性。在流产胎儿中，52%的胎儿大脑、22%的肾脏、18%的骨骼肌和4%的心脏检测到犬新孢子虫DNA。在20个胎儿的子集中，PCR阳性病例（55%，11/20）高于血清阳性奶牛（40%，8/20），但这20头奶牛血液样本的PCR结果均为阴性。813份样本的血清阳性率为15.5%（北京样本的43.4%，天津样本的5.7%），而PCR阳性血液样本为0.9%。我们的研究表明，巢式PCR是流产胎儿中犬新孢子虫初步诊断的有价值诊断工具，而ELISA是检测从奶牛采集的血液样本的首选检测方法。这两种检测方法在确定牛流产是否与犬新孢子虫感染相关方面具有互补性。
