Abstract:

To understand the prevalence of soil-transmitted nematode (STN) infection in Zhejiang Province, a survey was carried out in Jiande city, a fixed monitoring site and in Xiaoshan, Fuyang, Linan Districts, Tonglu, Chun’an Counties, the five mobile monitoring sites of STN infections from 2015 to 2018 according to the requirements of Zhejiang Surveillance Plan and Implementing Approaches of STN. A total of 7 911 residents were enrolled in the survey, 145 of them were positive for STN infections and the infection rate was 1.83%. Among them, 4 cases were infected with Ascaris lumbricoides and Truchuris trichiura, and 137 cases were infected with hookworm. Enterobius vermicularis was not detected. The overall prevalence of STN decreased from 2.32% (89/3 829) in 2015 to 0.54% (11/2 044) in 2018, with a decrease rate of 76.72%. Hookworm larvae were cultured from 137 hookworm egg positive feces using test-tube filter paper culture method, 98 of them were larva-positive (71.53%). In which 80 cases were infected with Necator americanus, 13 cases with Ancylostoma duodenale and 5 cases were fixed infections. The infection rates of STN for male and female were 2.00% (77/3 845) and 1.67% (68/4 066), respectively. The highest infection rate was 3.20% (101/3 156) in the age group over 60, and the infection rate increased with age (χ² = 63.061, P < 0.01). With respect of education and occupational distribution, the highest prevalence of STN infection was found in students in junior middle school (2.07%, 48/2 313) and in farmers (2.13%, 144/6 763). Among 100 examined soil samples, the detection rate of A. lumbricoides eggs was 2.00% (2/100), and no hookworm larva was detected. From 2015 to 2018, the infection rate of STN in monitoring sites in Hangzhou showed a downward trend.

Key words: Soil-transmitted nematode, Investigation, Analysis