ABSTRACT
BACKGROUND: Soil-transmitted helminths (STHs), such as hookworm, roundworm and whipworm, and food-borne trematodiases, including Clonorchis sinensis, remain a public health problem worldwide, especially in tropical and subtropical regions. OBJECTIVE: We aimed to determine the current prevalence of these parasites in Guangxi, China, which is located in a subtropical region. METHODS: A cross-sectional study and a 4-year longitudinal surveillance study were carried out. Stool samples were collected and examined microscopically for parasite eggs using the modified Kato-Katz thick smear method. RESULTS: The study subjects selected using stratified random cluster sampling for the cross-sectional study and longitudinal surveillance study numbered 15,683 and 24,429, respectively. In the cross-sectional study, hookworm, roundworm, whipworm, pinworm, C. sinensis, and tapeworm were found. The total prevalence of soil-transmitted helminths (STHs) was 6.4% (95% CI, 6.0-6.8). The prevalences of C. sinensis, hookworm, roundworm, whipworm, and pinworm were 10.6%, 4.2%, 0.3%, 0.3%, and 1.8%, respectively. The prevalence of C. sinensis in males (14.0%, 95% CI, 13.3-14.8) was significantly higher than in females (7.2%, 95% CI, 6.7-7.8) (P = 0.0001). The prevalence also was significantly higher in the medical worker group (20.8%, 95% CI, 12.9-28.7) than in all other occupational groups (10.5%, 95% CI, 10.0-11.0) (P = 0.0001). The prevalence of hookworm in females (5.3%, 95% CI, 4.8-5.8) was significantly higher than in males (3.0%, 95% CI, 2.6-3.3) (P = 0.0001). In the longitudinal surveillance study, the prevalence of C. sinensis and STHs in 2016, 2017, 2018, and 2019 were 12.0%, 6.0%, 11.0%, and 10.0% and 2.6%, 2.8%, 1.5%, and 1.5%, respectively. CONCLUSIONS: Adult male and occupation of and medical workers are risk factors for infection with C. sinensis and hookworm. The prevalence rate of C. sinensis remains high while those of the other STHs are decreasing, suggesting that enhanced health education should be focused on C. sinensis in Guangxi.
ABSTRACT
OBJECTIVE: To describe the discovery of a residual foci of bancroftian filariasis in Fuchuan County where the disease was announced to have been eliminated, and reveal its epidemiologic feature. METHODS: The investigation was carried out from August 2007 to March 2008 among residents in Changtang village where the first case of filariasis was found and the neighboring villages. They were screened with two thick blood smears. Immunochromatographic technology (ICT) was conducted for those going out but returned and those in surrounding areas. Vector mosquitoes were collected and dissected to find filaria larvae. Historical documents were reviewed and relevant people were interviewed. RESULTS: In Changtang administrative village, 1052 residents were screened and 19 cases with microfilaremia were found in 2 natural villages, with a Mf-positive rate of 1.8% (5.1% in Gangshang and 1.4% in Yinshan respectively). No Mf-positive case was found in 4119 residents screened in other 3 villages. The average microfilaria density in the 19 cases was 17.37/60 +/- 1 blood. All the 19 cases belonged to 12 families, and 13 cases were relatives to each other, which showed a feature of spatial clustering and family clustering. More patients were identified in the age groups of 20-29 and 50-59, and 57.9% of them were older than 50 years. No larvae were found in 54 Culex pipiens fatigans dissected. CONCLUSION: The Changtang village is identified as a residual focus of bancroftian filariasis with a low, limited endemicity. More cases have been among the elderly with a low average microfilaremia.
