Journal of Tropical Diseases and Parasitology ›› 2024, Vol. 22 ›› Issue (5): 277-283.doi: 10.20199/j.issn.1672-2302.2024.05.005

• CONTROL STUDIES • Previous Articles     Next Articles

Distribution characteristics and spatio-temporal analysis of soil-transmitted nematode in the hilly areas of Sichuan Province from 2016 to 2023

WU Xiaohong(), TIAN Hongchun, LUO Jingwen, TIE Lei, DENG Xiu, ZHANG Suping, LIU Yang()   

  1. Sichuan Center for Disease Control and Prevention, Chengdu 610041, Sichuan Province, China
  • Received:2024-02-23 Online:2024-10-20 Published:2024-11-15
  • Contact: LIU Yang, E-mail: evita_6161@163.com

Abstract:

Objective To analyze the prevalence of soil-transmitted nematode in the hilly areas of Sichuan Province for evidences to scientifically develop the prevention and control measures. Methods From 2016 to 2023, we carried out surveillance in accordance with the requirements of Sichuan Provincial Surveillance Program for Hepatic Flukes and Soil-transmitted Nematode Diseases (for Trial implementation) by setting a certain number of monitoring sites yearly in the counties (cities/districts). The modified Kato-Katz thick smear method (one sample for two smears) was used to detect hookworm eggs, roundworm eggs and whipworm eggs in the fecal samples, and the infection rate was calculated. The differences of infection rates in the hilly areas were analyzed among different genders, ages, education levels and occupational groups. Software ArcGIS 10.7 was used to establish a spatial database for analyzing whether the infection rate of soil-transmitted nematode (hookworm, roundworm and whipworm) in the hilly areas of Sichuan Province was spatially clustered by using global spatial autocorrelation and local spatial autocorrelation. Results A total of 89 226 people in 70 hilly counties (cities/districts) in Sichuan Province were surveyed between 2016 and 2023, and soil-transmitted nematode infections were found in 8 075 people, with an infection rate of 9.05%. The infection rate of hookworm, roundworm and whipworm was 8.52% (7 602/89 226), 0.52% (465/89 226) and 0.17% (149/89 226), respectively. The co-infection rate was 0.15% (130/89 226). The infection rate of soil-transmitted nematode was different between males (8.68%, 3 725/42 912) and females (9.39%, 4 350/46 314), with significant difference (χ2=13.71, P<0.01). In population in different age group and educational level group, the infection rate climbed up generally with added ages and lower educations (χ2trend=1 675.73, 883.37, both P<0.01). By occupations, the infection rate was relatively higher in farmers and herdsmen (10.54%, 7 376/69 990), with significant difference (χ2=890.86, P<0.01). The infection rates of soil-transmitted nematodes >20.00%, 10.01%-20.00%, 5.01%-10.00%, 1.01%-5.00% and 0.01%-1.00% were associated with 8, 21, 19, 20 and 2 counties (districts/cities), respectively. Global spatial autocorrelation analysis showed that there was spatial aggregation in the distribution of soil-transmitted nematodes and hookworm infections (Moran′s I>0, Z>2.58, P<0.01). Local spatial autocorrelation analysis revealed that the number of counties (cities/districts) with "high-high", "high-low", "low-high" and "low-low" concentrations of soil-transmitted nematode infection rates accounted for 7, 2, 1 and 2, and the number of counties (cities/districts) with "high-high", "high-low", "low-high" and "low-low" hookworm infection rates were 7, 3, 1 and 2, respectively. Conclusion The infection rate of soil-transmitted nematode in the hilly areas of Sichuan Province is relatively high, and presents spatial aggregation, therefore comprehensive prevention and control should be strengthened in the key areas.

Key words: Soil-transmitted nematode, Hookworm, Infection rate, Spatial analysis, Hilly areas, Sichuan Province

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