Abstract:

To understand the infection status of soil-transmitted helminthes(STH) and the prevalence of clonorchiasis in Beijing from 2016 to 2020, and provide scientific basis for formulation of prevention and control measures. Three surveillance sites were set up every year in Beijing to survey the infection status of STH and clonorchiasis prevalence, including one fixed surveillance site and one mobile surveillance site for STH, and one mobile surveillance site for Clonorchis infection. Each surveillance site was divided into 5 parts according to the geographical directions, including the east, west, south, north and middle parts, and a township was randomly selected from each part. Then, an administrative village was randomly selected from each township, where 200 permanent residents over 3 years of age were randomly selected using the cluster sampling method. The participants were surveyed by fecal examination for helminth infection using the modified Kato-Katz thick smear method (one sample, two slide-readings). Children aged 3 to 9 years in the surveillance sites for STH further underwent pinworm infection examination using the anal transparent tape test. The data of clonorchiasis were obtained from the Infectious Disease Surveillance Reporting System and epidemiological investigation, the place and source of infection were investigated and analyzed retrospectively. A total of 15 200 residents were surveyed during 2016—2020, and 10 were found positive. The overall prevalence was 0.07% (10/15 200). The infection rate of Ascaris lumbricoides and pinworm was 0.06% (9/15 200) and 0.01% (2/15 200), respectively. No resident was found infected by Clonorchis sinensis. The infection rate was 0.13% (6/4 697) in mountainous areas, and 0.04% (4/10 503) in plain, hilly, and basin areas (P > 0.05). The infection rate in females was 0.09% (7/8 052), and that in males was 0.04% (3/7 148), with no significant difference (P > 0.05). The residents infected were between the ages of 33 and 65, and their occupation were mainly farmers (6 persons), followed by unemployed persons (2 persons). A total of 16 cases of clonorchiasis were reported in Beijing during 2016—2020. Among them, 14 cases had eaten sashimi and two cases had eaten insufficiently cooked fish. The infection rate of soil-transmitted helminths is very low. Rural areas in the suburbs and outer suburbs are the focus of prevention and control. Clonorchiasis cases were reported occasionally, thus surveillance and health education should be strengthened.

Key words: Soil-transmitted helminths, Clonorchiasis, Beijing City