History of Medicine
Beginning in the 1950s, the Chinese state mounted the Patriotic Health Campaigns to improve sanitation and public health. In 1958 the campaigns focused on the "the four pests": rats, sparrows, flies and mosquitoes. Later sparrows were removed from the list, and fleas and lice added. Snails were particularly targeted for eradication because they carried the debilitating disease of schistosomiasis. In addition to spreading disease, these vermin also ate food, chewed electrical wires, and thus disrupted the social fabric that Mao Zedong was trying to build in China. The campaigns were short-lived and unsuccessful – more enduring were the efforts to improve water quality and waste treatment, which led to dramatic reductions in the epidemic diseases of cholera, plague, and typhoid.