台南市牛隻Babcsia bovis感染之疫學、病理學及分子生物學

2005年4月份台南市發生2歲以上牛隻出現發熱、食慾不振、乳量下降、血紅素尿等疑似牛焦蟲病症狀之牧場計3場，總頭數計601頭，發病頭數31頭，發病率為5.15%(31/601)，致死率為45.1%(14/31)。剖檢2頭發病牛隻及進行病理學檢查、病原分離、聚合酶鏈鎖反應等檢測。依臨床症狀、血液抹片、脾臟沾抹片、病理學檢查、電子顯微鏡檢查、聚合酶鏈鎖反應及核酸定序結果，診斷為牛焦蟲病。親源關係分析發現與南非及美國分離株親源關係相近，核酸序列相似度高達98.8%。於6-10月間針對此3場感染乳牛場，進行牛焦蟲疫情監控，每二週噴灑牛避逃。消毒酪農區與畜舍內外環境並針對感染場疑似感染牛隻以Imizol(上標 ®)、強肝劑、維生素B群、輸液等對症療法，並於2005年7及10月份以聚合酶鏈鎖反應及間接螢光抗體試驗進行感染場全場之Babesia bovis與抗體檢測，發現7月份抗原檢出率低，抗體陽性率約為9.7%-21%；10月份抗原檢出率低，抗體陽性率約在24.1%-38.7%，各場抗體轉陽性率上昇，顯示監測場仍有牛焦蟲持續潛伏感染。因此持續加強場內消毒與陽性牛隻的檢除，可有效減少本病的帶原與傳播。

關鍵字

牛焦蟲病；間接螢光抗體染色；病理學；聚合酶連鎖反應

並列摘要

Bovine babesiosis was uncovered in Tainan city in April, 2005. A total number of 601 2-year-old suspected infected dairy cows in three cattle farms that suffered from fever, loss of appetite, decrease milk production, and hemoglobinuria were found during a large scale of epidemiologic studies of bovine babesiosis by Tainan Hsien Livestock Disease Control Center. Overall, the morbidity and mortality rates were 5.15% (31/601) and 45.1% (14/31), respectively. Based on the results of clinical symptoms, blood smears, pathology examinations, electron microscopy, polymerase chain reaction, and DNA sequencing, these outbreaks were diagnosed as Babesia bovis. In phylogenetic analysis, it was also uncovered that the Taiwanese strain (Babesia bovis) was closely related to South Africa and US strains and their nucleotide sequences exhibited 98.8% identity. Upon diagnosis, the suspected animals were treated with Imizol(superscript ®) and vitamin B, and farm environments of all three farms were disinfected. Polymerase chain reaction (PCRI and commercial indirect immunofluorescent antibody (IFA) test were also used to detect Babesia bovis and the seroprevalence in all three cattle farms from July to October, 2005. The positive rate for B. bovis detected by PCR was low and positive rates for Babesia bovis in July and October by IFA were 9.7%-21% and 24.1%-38.7%, respectively. The mean of anti-babesia antibodies in October was 22%-27% among all investigated farms, suggesting that although latent infections still occurred but bovine babesiosis seemed to be under control. Therefore, frequent disinfections of cattle farms and eradication of infected animals will effectively reduce latent infections and disease spread.

並列關鍵字

Bovine babaesis ； indirect immunofluorescent antibody test ； pathology ； polymerase chain reaction

國際替代計量

台南市牛隻Babcsia bovis感染之疫學、病理學及分子生物學

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