Hookworm Prevalence Fell Sharply in Rural China After Integrated Control Pilot

Hookworm infection prevalence dropped from 4.76% to 1.06% in six rural villages of Tiantai County, Zhejiang Province, China, following a one-year integrated control program, according to a repeated cross-sectional study published in PLOS Neglected Tropical Diseases. The overall prevalence declined by 77.73% between the 2022 baseline survey and the 2024 post-intervention survey conducted in the same villages.

In 2022, 1,218 individuals were examined by stool testing, and 58 were positive for hookworm infection. After a year of interventions that combined sanitation improvement, health education, deworming, and strengthened village-level management, a second cross-sectional survey in 2024 examined 1,222 individuals and detected 13 infections.

To account for the sparse number of post-intervention cases, the researchers used Firth penalized logistic regression, a method designed to handle sparse data and complete separation in small samples. Adjusting for sex, age group, educational level, occupation, and village, the odds of infection in the 2024 survey were significantly lower than in 2022, with an adjusted odds ratio of 0.223 (95% confidence interval: 0.125–0.399, P < 0.001).

The analysis also identified groups carrying a disproportionate share of remaining infections. Male sex, primary education or below, and residence in the villages of Qianyang, Xiatang, or Xiaqiao were each associated with higher odds of hookworm infection, suggesting that transmission in the county is concentrated in specific communities and demographic groups rather than evenly distributed.

Hookworm infection remains a neglected tropical disease in rural areas where low-level transmission can persist despite long-term control efforts. The study’s design—repeated surveys in the same villages before and after intervention—offers unusually direct evidence of change over time at the village level, where stool examination provided a consistent detection method across both survey years.

The authors caution, however, that the absence of non-intervention control villages limits causal attribution. The observed reduction is an association with program implementation in the same villages, not a demonstration that any single component caused it.

The findings indicate that sustained surveillance and targeted interventions remain necessary for high-risk populations and villages. With prevalence reduced but not eliminated, the study suggests that low-level hookworm transmission in rural Zhejiang may be pushed further down through continued monitoring and efforts focused on the groups and villages where infection odds remain highest.

Subject of Research: Hookworm prevalence before and after an integrated control pilot in rural Zhejiang Province, China

Article Title: A comparative analysis of baseline and post-intervention surveillance in a hookworm control pilot: Evidence from Tiantai County, Zhejiang Province, 2022–2024

Article References: Gao, Q., Hu, H., Ge, J., Pang, W., Chen, Y., Chen, B., Zheng, X., Shen, W., Sun, J., & Lin, H. (2026). A comparative analysis of baseline and post-intervention surveillance in a hookworm control pilot: Evidence from Tiantai County, Zhejiang Province, 2022–2024. PLOS Neglected Tropical Diseases, 20(10), e0014835. https://doi.org/10.1371/journal.pntd.0014835

Image Credits: AI Generated

DOI: 10.1371/journal.pntd.0014835

Keywords: hookworm, neglected tropical diseases, China, Zhejiang, integrated control, deworming, sanitation, health education, cross-sectional study, parasitology, public health, surveillance