犬貓艾利希體症之研究

外文標題: 
A Study on Canine and Feline Ehrlichiosis
校院系所: 
屏東科技大學 獸醫學系
指導教授: 
林孫權
劉宏仁
出版年份: 
2000年
主題類別: 
摘要: 

為了確定台灣地區犬隻所感染之艾利希體菌之種別,建立快速正確的實驗室診斷方法,作為台灣地區本病疫情之掌控依據,且利於本病之早期診斷,於1999年6 月至2000年3月間,以國立屏東科技大學附設教學動物醫院門診犬貓病例隨機採取血液,並於高雄市採集臨床上健康貓隻血液,研發犬艾利希體症PCR診斷技術,並比較血液塗抹片檢查法、血清IFA測定法及PCR檢驗法等三項檢驗法之臨床實用價值。110個病例以EC1-4引子對進行巢式PCR,結果犬隻病例呈陽性反應者(產物約520bp)為20% (22/110);貓隻病例為11.76% (2/17),其中的56個病例同時以EE1-4引子對進行巢式PCR後,結果呈陽性反應者(產物約930bp)佔3.57% (2/56)。第一組PCR產物經定序,並以DNASTART軟體比對證實所有PCR產物皆為E. canis之16S rRNA,與標準株(M73221)序列相似度達97%以上。110個犬病例中隨機取樣60個血清樣本進行間接螢光抗體試驗(IFA),結果呈陽性反應者佔40% (24/60),呈陰性反應者60% (33/60)。16個貓隻病例均呈IFA陰性反應,且所有貓隻病例皆無法在末梢血液中見到細胞質含偶氮顆粒樣包涵體之淋巴球。PCR陽性犬隻中17個行血液學檢查,只有5個病例(29.41%)血液塗抹片中出現艾利希體菌包涵體(morulae),而66個PCR陰性病例,細胞質含偶氮顆粒樣包涵體之淋巴球出現率小於20%者佔93.94% (62/66),其絕對數低於600/ml者佔95.52% (64/66)。從本研究發現,過去被忽略末梢血液細胞質含偶氮顆粒樣包涵體之淋巴球數目,已證明可作為犬隻感染艾利希體臨床診斷之依據。本研究亦發現,以血液作為樣本時,三種檢驗法中IFA法之敏感性最高,PCR法次之,血液塗抹片之桑葚體檢出率最低;而特異性方面,以PCR法最高,IFA法次之,血液塗抹片法最低。此外,本研究發現貓隻感染E. canis為台灣地區首次之發生病例報告。

外文摘要: 

The purpose of this study was to idenitify Ehrlichia species in dogs and cats in Taiwan, and to establish a quick and accurate laboratory diagnostic method to assist diagnosis and control of this particular disease in dogs and cats. We collected canine and feline blood samples randomly from clinically cases at Department of Teaching Animal Hospital, National Pingtung University of Science and Technology, and feline blood samples from clinical healthy cats in Kaohsiung city in June, 1999 to March, 2000. The samples were used to develop PCR diagnostic technique for detecting Ehrlichia species, and to compare results among PCR test, IFA test and blood smear examination based on value of clinical application. The results: 110 dogs and 17 cats were amplified with nested PCR by EC1 to 4 primers. Twenty-two out of 110 dogs (20%) and two out of 17 cats (11.76%) assumed positive. Fifty-four dogs were amplified with nested PCR by EE1 to 4 primers. Two out of 56 dogs (3.57%) assumed positive. The former products were sequenced and collated with standard strain (M73221) by DNASTART software, and confirmed that all of them were E. canis. The sequence similarities of 16S rDNA genes among them were above 97%. Results of IFA test showed 40% of dogs (24/60) were IFA test positive, 60% of dogs (36/60) were IFA test negative. All of these cats were IFA negative. Ehrlichial inclusion was not seen in peripheral lymphocytes of all cats. Ehrlichial morulae in peripheral blood cells were found in 5 of 17 cases of PCR positive dogs. The percentage of peripheral lymphocytes containing elementary bodies (EB) and/or initial bodies (IB) less than 20% was found in 93.94% (62/66) of PCR negative dogs; and the absolute number of similar lymphocytes less than 600/ml was found in 95.52% (64/66) of PCR negative dogs. It is, thus, from the present paper, suggested that the number of peripheral lymphocytes containing EB and/or IB, ignored previously, could be clinically used as evidence of ehrlichial infection in dogs. It was also found, from the present study, that sensitivity was highest in IFA test, moderate in PCR test and lowest in presence of morula in blood smear examination; while specificity was highest in PCR test, moderate in IFA test and lowest in blood smear examination for detection of canine and feline ehrlichiosis using blood as test sample. Besides, occurrence of infection of E. canis in cats found the present paper is the first case report in Taiwan.