CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES ›› 2023, Vol. 41 ›› Issue (4): 464-469.doi: 10.12140/j.issn.1000-7423.2023.04.011

• ORIGINAL ARTICLES • Previous Articles     Next Articles

Survey on Angiostrongylus cantonensis infection in common snails in Yunnan Province from 2017 to 2022

ZHANG Juan(), TAO Hong, LI Yanzhong, WANG Tingting, YANG Jingjing, XIANG Yibin, CHEN Yishan, ZHOU Xiaomei*()   

  1. Yunnan Province Center for Disease Control and Prevention, Kunming 650034, China
  • Received:2023-02-20 Revised:2023-07-18 Online:2023-08-30 Published:2023-09-06
  • Contact: *E-mail: 13888979767@163.com

Abstract:

Objective To investigate the prevalence and characteristics of Angiostrongylus cantonensis infection in snails in parts of Yunnan Province. Methods Fresh snails were collected in the counties (districts) of 16 prefectures (cities) in Yunnan Province from public places, wild environment, farmers' markets, and the food material sold in restaurants, during April to October every year in 2017—2022. Each snail sample weights approximately 1 kg. Suspected larvae were observed and identified for species under optical microscope by enzyme digestion method, and the third-stage larvae of A. cantonensis were detected. Results A total of 2 402 samples of snails were collected and examined from 2017 to 2022, among them, 217 samples were found positive, with a total positive rate of 9.03%. The positive rate of snails collected in different years showed a decreasing trend year by year. The highest positive rate was seen in 2018 (15.05%) and the lowest rate was seen in 2022(3.36%) (χ2 = 55.427, P < 0.01). Among different snails, the Achatina folia infection rate was the highest, reaching 47.06% (88/187), followed by Pomacea canaliculata (7.89%, 50/634), the infection rates in Bellamya aeruginosa and Cipangopaludina cahayensis were 4.57% (54/1 181) and 6.25% (25/400), respectively (χ2 = 362.406, P < 0.01). A. cantonensis was detected in snail samples from 15 cities in the province except for Nujiang prefecture, and the positive rate of A. cantonensis in samples collected from Honghe prefecture was the highest, with 19.75% (63/319), followed by Xishuangbanna (19.69%, 51/259), Pu'er (9.52%, 12/126), Yuxi (9.09%, 16/176), etc (χ2 = 123.135, P < 0.01). In different sampling environments, the snail-positive rate was the highest in public places such as parks, which was 33.33% (28/84), in field environments such as fields and rivers, which was 17.61% (50/284), in farmers' markets, which was 6.94% (130/1 872), and in restaurants, which was 5.56 (χ2 = 98.076, P < 0.01). Among the snail samples collected in different months, the A. cantonensis positive rate was the highest in June, accounting for 50.00% (14/28). The lowest was 4.36% (18/413) in May (χ2 = 117.157, P < 0.01). Conclusion A. cantonensis infection was found in fresh snails collected from wild environment and commercial markets in Yunnan Province among which A. fulica and P. canaliculata showed higher infection rate.

Key words: Angiostrongylus cantonensis, Snail, Positive rate, Investigation and analysis, Yunnan

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