利用Wolbachia spp. 之特異性引子建立犬、貓心絲蟲症( Canine and Feline heartworm disease)感染之核酸診斷技術

Abstract

犬心絲蟲（ Dirofilaria immitis ）為一種寄生在狗、貓、狐、狼心臟及肺動脈的寄生蟲疾病。屬於 Filaroididae 科的 Dirofilaria 屬，往往造成感染動物的臨床症狀且影響其心臟功能。 目前犬心絲蟲的判定為臨床症狀、血液濕抹片中見到microfilaria的出現，加上商品化的ELISA 試劑（enzyme-linked immunosorbent assay）偵測。狗為 D.immitis 的固有宿主，可由以上方法得知心絲蟲的感染與否。在貓，大部份的貓在表皮血液中幾乎看不到幼絲蟲，但可能有具代表性的放射線學檢查結果或陽性的心絲蟲抗原 ELISA 試驗結果。 由於貓是偶然宿主, 故感染的蟲體數量很少 ， 所呈現的抗原量相對也低 ， 所以我們很可能會忽略貓的心絲蟲感染症 。在貓感染D.immitis 在血中見到 microfilaria 的機會很低，加上貓感染 D.immitis 只要幾隻成蟲寄生即可造成死亡。 Wolbachia spp.為一種垂直傳播的絕對細胞內寄生性立克次體，寄生在節肢動物及絲蟲體上，而它在絲蟲症上扮演著十分重要的角色。 D. immitis 蟲體上帶有 Wol. spp. ，兩者之間的關係目前仍有許多人探討。 本研究的目的在於利用聚合酶鍊鎖反應（ polymerase-chain-reaction；PCR ）之檢測 , 以利於日後建立犬、貓心絲蟲感染症在臨床上的診斷方法。 並於建立診斷方法後調查犬、貓感染 D. immitis 的盛行率以及探討 D. immitis 上存有Wol. spp. 的比率 。

Abstract The heartworm, Dirofilaria immitis, is a mosquito-borne pathogenic parasite of canids. It has also been found in other animals, such as seals, raccoons, as well as cats. The adult worms normally habitat in the right ventricle and pulmonary arteries. Cats usually tend to harbor very few and unisex adult worms and thus usually to remain amicrofilaremic. Additionally, cats usually fall victims to sudden death as a result of aberrantly migrating heatworms. Consequently, there is hardly reliable diagnostic method capable to identify the status of infection. Wolbachia is an obligate endosymbiont bacteria harbored by many arthropods and filarial worms, including D. immitis. The first description of Wol. spp. was made in 1924, when it was detected in the ovaries of the mosquito Culex pipiens and classified as an unnamed Rickettsia. All isolates of filarial parasites studied so far by PCR are infected with this bacteria. We develop nucleotide diagnostic technique of dirofilariasis in cat and dog by study the relationships between Wol. spp. and D. immitis . The purpose of the study contain: (1) Prevalance survey of cat and dog dirofilariasis. (2) Try to construct a clinical diagnostic technique of D.immitis infection in cat by PCR.