CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES ›› 2021, Vol. 39 ›› Issue (2): 273-277.doi: 10.12140/j.issn.1000-7423.2021.02.024

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Current status of Ascaris lumbricoides infection in populations in Yunan Province, 2015

ZI Jin-rong1(), WANG Li-bo2, YANG Ya-ming1, LI Ben-fu1, YAN Xin-liu1, PENG Jia1, CAI Xuan1, WANG Zheng-qing1, DU Zun-wei1, WU Fang-wei1,*()   

  1. 1 Yunnan Institute of Parasitic Diseases, Pu’er 665000, China
    2 Pu’er University, Pu’er 665000, China
  • Received:2020-06-24 Revised:2020-09-14 Online:2021-04-30 Published:2021-04-30
  • Contact: WU Fang-wei E-mail:1134797190@qq.com;wufangwei-03@126.com

Abstract:

To understand and analyze the infection status of Ascaris lumbricoides in Yunnan Province, a cross-sectional survey was conducted according to the National Survey Program and Implementation Details of Key Parasitic Diseases in 2015. Twenty sites of 10 counties (cities) were selected using the stratified cluster sampling method and stool samples were collected from no less than 250 permanent residents (≥ 1 year old) per site for microscopical examination using modified Kato-Katz thick smear method (two-reading/sample). A total of 5 067 participants were enrolled and 381 of them were infected with A. lumbricoides, with an overall prevalence of 7.5%. Among the 381 residents, the proportions of infection with unfertilized Ascaris eggs, fertilized Ascaris eggs and a mixture of both were 42.5%, 39.4% and 18.1%, respectively. The proportions of mild, moderate and heavy infections were 68.0%, 29.1% and 2.9%, respectively. Different detection rates were observed among different ecological regions, i.e., the eastern Tibet-western Sichuan region had the highest detection rate (16.6%, 211/1 271), in which the Gongshan County had the highest rate (26.2%, 200/762), and Ascaris infection was detected in all 10 counties of this region. There was a statistically significant difference in the detection rate among different ecological regions and counties (P < 0.01). The detection rate in females (8.2%, 218/2 645) was higher than that in males (6.7%, 163/2 422) (P > 0.05). All age groups were found with Ascaris infection, but the highest detection rate was found in children under 10 years (18.1%, 119/657) (P < 0.01). The Dulong ethnicity had the highest detection rate (48.9%, 131/268) among ethnic groups (P < 0.01). Teachers had an detection rate of (2/6), while the pre-school children had an infection rate of 21.4% (93/435). Among the examinees with different educational levels, the illiterate had the highest detection rate (13.1%, 177/1347) (P < 0.01). The detection rate of Ascaris lumbricoides in Yunnan Province showed significant differences with regard to age, ethnicity, occupation, and educational level (P < 0.01). Overall, the detection rate showed a differential distribution among regions, with particularly high rate and infection intensity in some areas.

Key words: Yunnan Province, Ascaris lumbricoides, detection rate, Survey

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