[Surveillance of soil-transmitted nematode infections in Zhenjiang City from 2006 to 2018]

To understand the epidemic trend of soil-transmitted nematodiasis in Zhenjiang City from 2006 to 2018, so as to provide evidence for formulating targeted control measures.

The permanent residents at ages of 3 years and greater and the immigrants who had lived in Zhenjiang City for more than one year were selected as the study subjects. Fecal samples were collected, and the soil-transmitted nematode eggs were detected in fecal samples with the modified Kato-Katz technique (three smears from one stool sample), while the children at ages of 12 years and lower were tested for Enterobius vermicularis eggs using the adhesive cellophane-tape perianal swab method. The prevalence and intensity of parasitic infections were estimated in Zhenjiang City each year from 2006 to 2018, and the data pertaining to the deworming for soil-transmitted nematode infections were collected during the study period.

A total of 202 880 person-times were subjected to stool examinations in Zhenjiang City from 2006 to 2018, and 946 persons were detected with soil-transmitted nematode infections, with a mean prevalence of 0.47%. The overall prevalence of human soil-transmitted nematode infections appeared a decline tendency (P < 0.01), with a reduction from 1.10% in 2006 to 0.11% in 2018, and there was a region-specific overall prevalence (P < 0.01), with the highest prevalence seen in Runzhou District (1.65%) and the lowest detected in New District (0.04%). The mean prevalence of human Ascaris lumbricoides, hookworm and Trichuris trichiura infections was 0.33%, 0.09% and 0.04% in Zhenjiang City, respectively, and showed a decline tendency year by year from 2006 to 2018 (P < 0.01). Among all infections, mild infections were predominant. During the period from 2006 through 2018, a total of 45 427 children were examined in Zhenjiang City from 2006 to 2018, and 145 children were positive for E. vermicularis infections, with a mean prevalence of 0.32%. The prevalence of E. vermicularis infections decreased from 1.33% in 2006 to 0.22% in 2018 in children, and the overall prevalence appeared a decline tendency (P < 0.01). A single parasite infection was predominant in soil-transmitted nematode infections (97.46%), and mixed infection of two parasites were mainly detected before 2007. A total of 535 089 person-times received deworming in Zhenjiang City from 2006 to 2018, and the rate of adverse events was 0.002%.

Currently, the soil-transmitted nematode infection is at a low level in Zhenjiang City, and the overall prevalence of soil-transmitted nematode infections shows a decline tendency year by year. The surveillance and health education of soil-transmitted nematodiasis should be further intensified to consolidate the control achievements.