Schistosomiasis Reemergence in China

For the past five decades, China has been successful in controlling schistosomiasis in endemic areas. Through snail control, chemotherapy, health education, and access to clean water the disease was eradicated in three provinces, in Shanghai, and in the Guangxi Province. In Sichuan at the end of 2004, however, schistosomiasis reemerged in seven counties where disease transmission was previously controlled.

Schistosomiasis is a neglected tropical disease that is spread to humans by contact with snail-infested waters. These snails are infected with the parasite Schistosoma and live in fresh water. In Sichuan, China the disease was first documented in 1924; however, it wasn’t until 1985 that transmission control was achieved in 20 counties, then increased to 21 counties in 2001. Reemergence of schistosomiasis in seven  of these counties may be attributable to sociopolitical, economic, environmental, and surveillance system changes, including:

  • decreased funding for health workers
  • decreased awareness of the issue among the local government and lack of coordination between government departments (public health, agricultural, husbandry departments, for example)
  • increased establishment of snail habitats (creation of irrigation canals, for example)
  • ineffective surveillance systems post-control of the disease

To regain control of schistosomiasis transmission, researchers call for a combination of chemotherapy, snail control, and improvements in sanitation. Increased funding in environmental modification and rural sanitation would also attribute to getting transmission under control.

Before solutions are implemented, however, several considerations must be taken into account. Transmission of the disease varies from area to area. In mountainous regions, snails infected with the Schistosoma reside in the irrigation canals on farms, which make farmers the most vulnerable population for contacting the disease. In other areas where the infected snails inhabit lakes and marshlands, bovine are largely responsible for transmission. Because of differing transmission cycles, it is important to develop solutions that are generalizable over a variety of regions. Also, looking toward inter-sectoral funding where resources can come from departments outside the ministry of health such as those that govern energy, water, agricultural, and animal resources will also help health officials regain control of schistosomiasis in Sichaun.

About Linda Diep

Linda Diep is the Communications and Grassroots Assistant with the Global Network for Neglected Tropical Diseases focusing on media relations, strategy, and our Just 50 Cents grassroots efforts.

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