我国结膜吸吮线虫病流行因素及传播机制的研究

目的为探讨我国结膜吸吮线虫病流行因素和传播机制。方法我们调查了安徽淮北地区的犬、猫和野兔自然感染结膜吸吮线虫成虫和变色纵眼果蝇、家蝇自然感染结膜吸吮线虫幼虫情况，并用结膜吸吮线虫初产蚴喂饲变色纵眼果蝇、家蝇实验感染的观察。结果检查犬305只，阳性234只占76.7％;猫14只阳性4只占28.6％;野兔59只中阳性6只，占10.2％。检查变色纵眼果蝇（Amiotavariegata）737只，自然感染结膜吸吮线虫幼虫者12只占1.6％。于1989年我们证实变色纵眼果蝇为结膜吸吮线虫中间宿主，而家蝇并不是。幼虫在果蝇体内发育过程为：被食入的初产的24h内脱去鞘膜。第2—3d钻过胃肠壁入血腔，多数幼虫侵入雄果蝇睾丸或雌蝇血腔壁形成“虫泡囊”。在囊内经腊肠期、感染前期和感染期连续发育并蜕二次皮。感染期蚴钻破虫泡囊，移行到头部和口器。当感染的果蝇再次呼吸终宿主（犬、猫及人）泪液时，幼虫进入眼结膜囊内，经2次蜕皮发育为成虫。感染后35d，雌虫开始产出初产蚴。成虫寿命可达30个月以上。结论结膜吸吮线虫最重要的保虫宿主是犬，其中间宿主是变色纵眼果蝇，在流行区传播媒介为该种果蝇。

STUDIES ON EPIDEMIOLOGIC FACTOR OF THELAZIA CALLIPAEDA IN CHINA

AIM In order to inquire into on epidemiologic factor and transmission mechanisms of Thlazia callipaeda in China. METHODS We examined T. callipaeda infection in the conjunction sac of dogs,cats and wild rabbits in Anhui province,and dissected Amiota variegata and Musca of the natural and experimental infection for T. callipaeda respectively. RESULTs We found 76. 7% (234/305) dogs infected, 28.6% (4/14) cats and 10. 2% (6/59) wild rabbits in Huabei area of Anhui province. A. variegata were discovered as intermediate host of this parasite in China in 1989. The natural and experimental infective rates of A. variegata were l. 6% (12/737) and 17. 4% (106/608) respectively. But none of Musca was infected with T. callipaeda larva in our research. The newborn larvae of T. callipaeda were fed to A. variegata in experimental infection. The larvae penetrated the alimentary tract and entered into the testis of male A. variegata or the wall of hemocoel of the female. Developing larvae were always found in the capsules located in tissues of A. variegata. The developmental process of T. Callipaeda laevae in A. variegata was separated into three successive stages,included sausage,preinfective and infectve stage. There was a mould of cuticle between each two stages. The infective larvae migrated through the hemocoel to the head and proboscis of A. variegata. Complete laevae development in A. variegata reqired 14- 17 days at suitable temperature. Infective larvae entered the conjunctive sac of the final hosts(dog,cat,rabbit and man),when infective A. variegata sucked the tears of the final hosts. They grew into adults with two ecdysis in this process of development. After infection for 35 days,the adult female began to produce newborn larvae. The longest life-span of T. callipaeda was more than 30 months. CONCLUSION Dog was confirmed most important final host of T. callipaeda,and Amiota variegata was its intermediate host. In this focus the typical vector is A. variegata in China.