结膜吸吮线虫生活史的进一步研究(英)

Further Studies on the Life Cycle of Thelazia callipaeda in China

目的 进一步研究我国结膜吸吮线虫(Thelazia callipaeda)生活史及其中间宿主。 方法 采集自然感染的家蝇和冈田氏绕眼果蝇(Amiota okadai),检出线虫幼虫,分别接种动物;用结膜吸吮线虫初产蚴分别喂饲实验室繁殖的第二代家蝇和冈田氏绕眼果蝇。 结果 自流行区采集冈田氏绕眼果蝇493只,从其体内检获34条幼虫,接种2只家兔和1只家犬眼内,经18～44 d观察,获成虫11条。结膜吸吮线虫初产蚴在冈田氏绕眼果蝇消化道内脱鞘,钻过肠壁进入血腔,在雄蝇睾丸和雌蝇血腔膜形成虫泡囊。幼虫经2次蜕皮(需14～17 d)发育为感染性幼虫,然后经颈部移行至喙。当果蝇吸食人及犬、猫眼部分泌物时进入终宿主眼内,经2次蜕皮发育为成虫后,产出幼虫。成虫寿命可达30个月以上。 结论 我国结膜吸吮线虫的中间宿主为冈田氏绕眼果蝇。

Objective To further investigate the life cycle and intermediate host of Thelazia callipaeda in China. Methods Dogs and rabbits were experimentally infected with larvae of T. callipaeda from naturally infected houseflies Musca spp. and fruit flies Amiota okadai. Houseflies and A. okadai bred in laboratory were fed with newborn larvae of T. callipaeda to define the intermediate host of the eye worm. Results Two rabbits and one dog were infected with 34 larvae of T. callipaeda taken from 493 naturally infected A. okadai. As a consequence, 11 adult worms were harvested from the experimentally infected animals 18 to 44 days after infection. The development process of T. callipaeda larvae in A. okadai included three successive stages. The infective larvae migrated through the hemocoel to the head and proboscis of A. okadai. Complete larval development in A. okadai required 14 - 17 days under appropriate temperature. Infective larvae entered the conjunctiva sac of the definitive hosts (dogs, cats, and man) when infected A. okadai sucked their eye secretions. The larvae grew into adults, with two ecdyses in the process of development. The adult females began to produce newborn larvae in 35 days after infection. The longest life-span of T. callipaeda was more than 30 months. Conclusion A. okadai is the intermediate host of T. callipaeda in China.