台灣乳牛場犬新孢蟲症盛行率調查及建立即時定量聚合酶連鎖反應診斷犬新孢蟲症

犬新孢蟲症 (Neosporosis) 為牛隻流產主因之一，對酪農產業造成嚴重損失。本研究調查台灣乳牛犬新孢蟲症盛行率並建立以即時定量聚合酶連鎖反應 (Real-time PCR) 診斷犬新孢蟲症之模式。本研究於2017年4月至2018年2月間自32場乳牛牧場採取361頭懷孕母牛血液樣本進行ELISA、Real-time PCR和Nested PCR檢測，並將檢測結果與採樣牧場及牛隻基本資料進行分析。三種檢測結果陽性率分別為26.3% (95/361)、17.2% (62/361) 和2.2% (8/361)。血清學檢測部分，陽性率與2000年文獻相比略有下降，但在不同場次間差異極大，陽性場比例為75.0% (24/32)，在曾發生嚴重流產問題、年流產率較高之牧場及有流產紀錄牛隻陽性率顯著較高。在本次研究中亦調查牧場犬隻飼養與否與犬新孢蟲症之關聯性，結果顯示牧場飼養犬隻比例為81.3% (26/32)，在是否飼養犬隻牧場間血清陽性率沒有顯著差異，然而在有自由活動犬隻牧場之血清陽性率則顯著較高。分子生物學檢測部分，Nested PCR檢測陽性率低於Real-time PCR，三種檢測方式在統計上不具一致性。與過往文獻數據相比，本研究結果中犬新孢蟲症盛行率下降，但仍普遍存在台灣乳牛牧場，且與牧場流產問題關係密切。此外，在牧場普遍飼養犬隻情況下，良好管控牧場內外及周圍犬隻的活動狀況應對犬新孢蟲症疫情有所幫助。綜觀三種檢測方式，Real-time PCR為較適合使用於檢測血液中微量犬新孢蟲DNA之診斷方式。

關鍵字

犬新孢蟲症；流產；酵素連結免疫吸附分析法；即時聚合酶連鎖反應；乳牛

並列摘要

Neosporosis, one of the major causes of cattle abortion, has struck the dairy industry seriously. This study was investigated the prevalence of neosporosis in dairy farms and quantitative real-time polymerase chain reaction (Real-time PCR) assay was established for diagnosis of neosporosis in Taiwan. From April 2017 to February 2018, total 361 blood samples were collected from pregnant cows within 32 dairy farms, and were conducted by ELISA, real-time PCR and nested PCR against Neospora caninum, further the results were analyzed with the information of farms and cattle. The positive rates of these three tests were 26.3% (95/361), 17.2% (62/361) and 2.2% (8/361), respectively. In serological detection, the seropositive rate was decreased compared with the study in 2000, but varied a lot among different farms. The seropositive farm rate was 75.0% (24/32). There were significant high seropositive rates in the farms have had severe abortion in the past, abortion rate above 5%, and cattle had abortion history. The study revealed the ratio of dogs raising in farms as 81.3% (26/32). Although there was no significant difference in seropositive rate between dog-raising or not, there was a significant difference between free-roaming or confined dogs. In molecule-biological detection, the positive rate of nested PCR was lower than real-time PCR. There was no consistency in statistical analysis between these three methods. Even though the seroprevalence in this study decreased comparing with the data in 2000, Neospora caninum is still present in dairy cows in Taiwan and strongly related to abortive issue. Under the situation of high tendency keeping dogs in farms, strict restriction of canine active range may be a helpful method to control neosporosis. Real-time PCR is able to detect minute quantity pathogens in blood advantageously, and it could be used in clinical or subclinical investigation, which provide more sensitive and rapid way to diagnosis.

並列關鍵字

Neosporosis ； abortion ； Enzyme linked immunosorbent assay ； Real-time polymerase chain reaction ； dairy cow

參考文獻

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