Objective: To investigate the prevalence of soil-borne nematode infections among rural residents in Tiantai County, Zhejiang Province, so as to provide insights into improving the control strategy. Methods: According to the Zhejiang Provincial Surveillance Programme on Soil-borne Nematodiasis and Clonorchiasis, 5 administrative villages were randomly selected in Tiantai County according to geographical locations on April, 2021, and all permanent residents at ages of 3 years and older were sampled from each village using a cluster sampling method. Subjects' gender, age, occupation, education level and deworming were collected. Subjects' stool samples were collected, and soil-borne nematode eggs were detected using the modified Kato-Katz technique, and larval culture was performed using a filter-paper culture method among hookworm egg positives for identification of hookworm species. In addition, the intensity of infection was evaluated using hookworm eggs per gram stool sample. Results: A total of 1 013 residents participated in the survey, including 495 men (48.86%) and 518 women (51.14%), and there were 502 participants at ages of 51 to 70 years (49.56%), 874 farmers (86.28%) and 436 subjects with an education level of primary school (43.04%). However, no subjects received deworming. The prevalence of hookworm infections was 3.85% among the study subjects, and only Necator americanus was identified. There were 31 cases with mild infections (79.49%), 5 cases with moderate infections (12.82%) and 3 cases with severe infections (7.69%), and all infections occurred in farmers. The prevalence of hookworm infections was 3.84% among men and 3.86% among women. No hookworm infection was detected among residents at ages of <41 years, and the prevalence of hookworm infections appeared a tendency towards a rise with age among residents at ages of 51 years and older (χ2trend=24.091, P<0.001), while the prevalence of hookworm infections appeared a tendency towards a decline with educational levels among residents (χ2trend=19.534, P<0.001). The greatest prevalence of hookworm infections was found in Qianyang Village (10.95%). Conclusions Hookworm disease is the predominant type of soil-borne nematodiasis in Tiantai County, and the middle-aged and elderly farmers with a low education level are high-risk populations for soil-borne nematodiasis control.

Abstract On April 25, 2021, a case with hookworm infections was identified during the surveillance of soil-borne nematodiasis by Tiantai Center for Disease Control and Prevention, Taizhou City, Zhejiang Province. The patients was admitted to a county people's hospital due to dizziness and limb weakness on July 24, 2020. Laboratory tests showed 2.5×1012/L red blood cell counts, 45 g/L hemoglobin, 3.4% eosinophil percentage, 4.7 μmol/L serum iron and <1 μg/L ferritin, and severe iron-deficiency anemia was initially diagnosed. Following treatment with blood transfusion and ion supplement, subsequent three routine blood tests indicated elevated eosinophil percentages. On April 25, 2021, hookworm eggs were detected in stool samples using Kate-Katz technique, and Necator americanus was identified with the test-tube filter-paper culture method. Severe iron-deficiency anemia caused by hookworm infections was diagnosed based on field epidemiological surveys and laboratory tests. The health education pertaining to parasitic disease control knowledge among residents and the diagnosis and treatment of parasitic diseases in medical institutions are recommended to be improved in rural areas to avoid misdiagnosis and missing diagnosis.

ObjectiveTo understand the prevalence of hookworm infection and its relevant behavioral factors in rural areas of Tiantai County， Zhejiang Province， and to provide scientific evidence for prevention and control of hookworm disease. MethodsBy using a stratified cluster random sampling strategy， local residents aged ≥3 years was divided into 5 districts according to geographical location； furthermore， those in one administrative village （surveillance site） were investigated in each district. Species of hookworm were identified by filter paper culture in vitro， and enterobius vermicularis eggs were detected by cellophane anal swab in children aged 3‒9 year. Risk factors were determined by questionnaire. ResultsA total of 1 013 residents were investigated in 5 surveillance sites. Thirty nine cases with hookworm infection were detected， with the total infection rate of 3.85% . All species detected were determined to be Necator americanus. The infection rate significantly differed across the towns （χ²=48.32， P<0.05）， with the highest rate in Nanping Town （10.95%） . It significantly differed by age groups （χ²=65.65， P<0.05）， with the highest rate in those aged >70 years （9.75%）. Furthermore， it decreased with educational background. It was significantly associated with fertilize with fresh manure （χ²=6.87， P<0.05） and barefoot labor （χ²=157.69， P<0.05）. ConclusionThe overall infection rate of hookworm in Tiantai County remains low. Dominant species of hookworm is hookworm Necator americanus. It is necessary to strengthen the advocacy of hookworm prevention and control knowledge， improve hygiene in work and life style， and increase self-protection awareness.