台灣地區待產乳牛與小牛小隱孢子蟲感染之調查

The Investigation of Cryptosporidium parvum Infection in Expectant Dairy Cows and Calves in Taiwan

李睿彧(Lee Jui-Yu)

指導教授 ： 李旭薰

國立屏東科技大學/獸醫學院/獸醫學系所/碩士(2018年)

https://doi.org/10.6346/THE.NPUST.VM.009.2018.D07

摘要

國外報告牛主要有四種隱孢子蟲 (Cryptosporidium)感染，分別是 C. parvum、C. bovis,、C. ryanae和 C. andersoni。其中以 C. parvum所造成的危害最大，在牛隻會造成下痢，導致經濟損失。較早的報告中提到 C. parvum主要感染族群為小牛；而較新的報告中發現，母牛帶原而使小牛一出生即感染的可能性頗高。本報告將把台灣分成4個區域，然後以 nested-PCR調查待產乳牛、小牛的 C. parvum盛行率，以及待產乳牛、小牛的飼養環境中的卵囊陽性率。同時也將進行問卷調查，詢問關於飼養環境的清洗頻率與是否消毒。試驗結果發現小牛 C. parvum盛行率26.5 % (60/226)，成牛盛行率19.7 % (39/198)，其中南部小牛盛行率33.6 % (36/107)顯著高於東部13.3 % (6/45) (P<0.05)，南部成牛盛行率25.6 % (23/90)顯著高於東部9.8 % (4/41) (P<0.05)。在環境方面，小牛欄樣本陽性率18 % (37/206)，小牛水桶樣本陽性率2.2 % (4/178)，待產區地板樣本陽性率 16.7 % (5/30)，待產區水槽樣本陽性率6.3 % (2/32)。場陽性率90 % (18/20)，4個區域內的場陽性率沒有顯著差異 (P>0.05)。而 C. parvum感染與下痢有顯著相關性 (odds ratio: 2.1; 95 % CI: 1.1–4)。目前結果顯示小牛環境與水桶清洗頻率降低與小牛感染 C. parvum沒有顯著相關性。待產區環境清潔頻率降低與小牛感染 C. parvum有顯著相關性 (odds
ratio: 6.8; 95 % CI: 2.2–20.9)。待產水槽清潔頻率降低與成牛感染 C. parvum有顯著相關性 (odds ratio: 9.5; 95 % CI: 2.6–34.8)。待產區有運動場與小牛感染 C. parvum有顯著相關性 (odds ratio: 0.08; 95 % CI: 0.01–0.5)。消毒劑的使用在小牛與小牛感染 C. parvum有顯著相關性 (odds ratio: 6.9; 95 % CI: 2.3–20.3)。在待產成牛與環境中皆可檢測到 C. parvum，顯示小牛有感染的機會；應當注意待產環境清潔，頻率下降會導致感染率上升。消毒劑的選用應當注意是否有效。

關鍵字

乳牛 ； 小隱孢子蟲 ； 盛行率 ； 飼養環境 ； 風險因子

並列摘要

There are four species of Cryptosporidium commonly reported in cattle; C. parvum, C. bovis, C. ryanae and C. andersoni. C. parvum has the highest pathogenicity among them. The most common clinical sign is diarrhea and causing considerable direct and indirect economic losses. Former studies indicated that calves are susceptible hosts to C. parvum. Moreover, recent studies pointed out the high possibility of calves infected Cryptosporidium right after being delivered due to the carrying of this pathogen by their dams. In this research, Taiwan was divided into four areas, and the investigation of the prevalence of C. parvum infection and the oocysts positive rates in the environment of the expectant dairy cows and calves was conducted by using nested polymerase chain reaction. It was revealed that calves’ prevalence was 26.5 % (60/226). Expectant cows’ prevalence was 19.7 % (39/198). The calves’ prevalence of southern Taiwan was 33.6 % (36/107), which is significantly higher than the prevalence of eastern Taiwan 13.3 % (6/45) (P<0.05). The expectant cows’ prevalence of southern Taiwan was 25.6 %
(23/90), which is significantly higher than the prevalence of eastern Taiwan 9.8 % (4/41) (P<0.05). Calves’ pen sample positive rates were 18 % (37/206). Calves’ bucket sample positive rates were 2.2 % (4/178). Expectant cows’ floor sample positive rates were 16.7 % (5/30). Expectant cows’ sink sample positive rates were 6.3 % (2/32). Farm positive rates was 90 % (18/20). C. parvum infection was significantly associated with diarrhea in calves (odds ratio: 2.1; 95 % CI: 1.1–4). The reduce of calves’ pens’ and buckets’ cleaning frequency wasn’t significantly associated with calves C. parvum infection rates. The reduce of expectant areas’ cleaning frequency was significantly associated with calves C. parvum infection rates (odds ratio: 6.8; 95 % CI: 2.2–20.9). The reduce of expectant sinks’ cleaning frequency was significantly associated with calves C. parvum infection rates (odds ratio: 9.5; 95 % CI: 2.6–34.8). The existence of outdoor yards in expectant areas was significantly associated with calves C. parvum infection rates (odds ratio: 0.08; 95 % CI: 0.01–0.5). The use of disinfectant was significantly associated with calves C. parvum infection rates (odds ratio: 6.9; 95 % CI: 2.3–20.3). Because both expectant cows and expectant areas can detect C. parvum, calves have chance to infect C. parvum. Farmer should pay attention at the cleanliness of expectant areas, the cleanliness of expectant sink and the efficacy of disinfectant.

並列關鍵字

Cryptosporidium parvum ； dairy cows ； environment ； prevalence ； risk factors

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