Research Highlights

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  • Clinical medicine

Published online: 11 February 2009 | doi:10.1038/nchina.2009.20

Parasitic diseases: Irrigation, sanitation, education

Jasmine Farsarakis

Introduction

© (2009) istockphoto.com/Wojtek Kryczka

Schistosomiasis, also known as snail fever, is a parasitic disease caused by the flatworm Schistosoma japonicum. The disease affects many people in developing countries, especially in areas where the water contains snails that carry the parasite. Past efforts to curb schistosomiasis with pesticides have done more damage to the environment than good to the people. Xiaonong Zhou at the Chinese Center for Disease Control and Prevention in Shanghai and co-workers¹ report a new intervention strategy that has successfully lowered the rates of infection to the country's target of 1%.

Schistosomiasis has a transmission cycle — humans and cattle are exposed to water contaminated by S. japonicum larvae from diseased snails, and faeces from infected humans and cattle serve to infect snails. The researchers suggested that this vicious cycle can be broken by addressing the sources of infection — the humans and cattle.

They tested this intervention strategy in villages in China. They removed cattle from use in grasslands endemic to snails by replacing them with modern farming equipment, improved sanitation and curbed the villagers' exposure to contaminated water by providing irrigation and sewage infrastructures. They also increased villagers' awareness of the disease through education.

The results were exemplary. After three transmission seasons, human infection rates were reduced from 11.3% to 0.7% in one intervention village, and infection in snails and the local water supply was eliminated entirely.

The results have important implications for the future of schistosomiasis control. China is now applying the intervention strategy to more than 60 other regions.

The authors of this work are from:
Ministry of Health, Beijing, China; Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, China; National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China; Jinxian Antischistosomiasis Station, Jinxian, China; Office for Schistosomiasis Control of Jiangxi Provincial Government, Nanchang, China; Bill and Melinda Gates Foundation, Beijing, China.

Reference

1. Wang, L. D. et al. A strategy to control transmission of Schistosoma japonicum in China. N. Engl. J. Med. 360, 121–128 (2009). | Article | PubMed | ChemPort |