title: Angiostrongylus cantonensis: scanning electron microscopic observations on the cuticle of moulting larvae.
abstract: Angiostrongylus cantonensis is a parasitic nematode that needs to develop in different hosts in different larval stages. Freshwater snails, such as Pomacea canaliculata, are the intermediate host, and rats are the definitive host. Periodic shedding of the cuticle (moulting) is an important biological process for the survival and development of the parasite in the intermediate and definitive hosts. However, there are few studies on the cuticle alterations between different stages of this parasite. In this study, we observed the ultrastructural appearance and changes of the cuticle of the 2nd/3rd stage larvae (L2/L3) and the 3rd/4th stage larvae (L3/L4) using a scanning electron microscope. We also first divided L2/L3 into late L2 and early L3. The late L2 lacked alae, but possessed a pull-chain-like fissure. Irregular alignment of spherical particles on the cuticle were noted compared to the L3. Alae appeared in the early L3. The old cuticle turned into a thin film-like structure which adhered to the new cuticle, and spherical particles were seen regularly arranged on the surface of this structure. Regular rectangular cavities were found on the surface of L3/L4. The caudal structure of L3/L4 was much larger than that of L3, but caudal inflation, such as seen in L4, was not observed. These results are the first to reveal the ultrastructural changes of the cuticle of A. cantonensis before and after moulting of L2/L3 and L3/L4.
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Xin
authors: X
authors: Zeng
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Jie
authors: J
authors: Wei
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Juan
authors: J
authors: Wang
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Feng
authors: F
authors: Wu
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Feng
authors: F
authors: Fung
authors: Department of Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Xiaoying
authors: X
authors: Wu
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Xi
authors: X
authors: Sun
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Huanqing
authors: H
authors: Zheng
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Zhiyue
authors: Z
authors: Lv
authors: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. ; Ministry of Education Key Laboratory of Control of Tropical Diseases, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors: Zhongdao
authors: Z
authors: Wu
mesh_terms: D017185:Angiostrongylus cantonensis / Q000502:physiology* / Q000648:ultrastructure*; D000818:Animals; D007814:Larva / Q000502:physiology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D018978:Molting
keywords: Angiostrongylus cantonensis; moulting larva; scanning electron microscopy