Abstract: Objective To observe the morphologic characteristics of Ⅲ stage larvae of Angiostrongylus cantonensis from Pomacea canaliculata. Methods P. canaliculata, the intermediate host snail of A. cantonensis, was infected with Ⅰstage larvae of A. cantonensis in laboratory. After 61 days, Ⅲ stage larvae of A. cantonensis were harvested from snail′s lungs and muscle of head-foot, followed by HE stain to observe morphological characteristics. Results The whole body of Ⅲ stage larva was curling with obtuse head. Its pharyngeal canal extends from the buccal hole on the top of the head to the intestines at the pharyngeal intestine joint place, with apex cauda and clear anal tube. The tegument of the Ⅲ stage larva was eosin-stained, with a transparent sheath outside of tegument. Some of the larvae cauda showed in circular cylinder, and some larvae presented ventral gland with two very short uterines which used to be the feature only showed in early Ⅳ stage larva. Conclusion Morphologicall characteristics of the Ⅲ stage larvae is helpful to better understand the life-cycle and the control of A. cantonensis.

Key words: Pomacea canaliculata, Angiostrongylus cantonensis, Ⅲ stage larvae, Morphology