INTERVIEW-China to remove cattle to combat "snail fever"
17 Oct 2006 06:18:35 GMT Source: Reuters
By Tan Ee Lyn BEIJING, Oct 17 (Reuters) - China may have finally found an answer to control "snail fever", an age-old disease caused by a parasite that leaves people so weak they are unable to work, a senior Chinese health official said. "Snail fever", or schistosomiasis, is a neglected tropical disease affecting developing countries and victims suffer fever, abdominal pain, cough, diarrhoea, fatigue and distended bellies in advanced stages of the illness. Although there are effective drugs, people get infected repeatedly because they are constantly exposed to the parasite, which thrives in paddy fields, freshwater lakes and rivers. China's answer to the problem comes in removing cattle -- a key host -- from the lifecycle of the culprit parasite, called schistosomes. Humans are also ideal hosts of the parasite. Scientists who carried out studies have proposed that farmers rely more on tractors than cattle to till the land to prevent the spread of the disease. "One cow can infect 15 people, we want to control the population of (working) cattle," Hao Yang, deputy director general of the bureau of diseases prevention and control at the Ministry of Health, told Reuters in an interview. Infected humans and cattle shed the parasite in their stools, which in turn infect freshwater snails in paddy fields and lakes. The snails then shed larvae, called cercariae, which are well-adapted to infecting mammals -- by tunnelling through the tiny pores on their skin. Some 840,000 people suffer from the disease in China. The liver and the spleen malfunction and victims are unable to expel waste, thereby causing the stomach to bloat up. "It is particularly serious in the provinces of Hubei, Hunan, Anhui, Jiangxi and Jiangsu. Some places in Sichuan and Yunnan are also hit," Hao saiD. In a 12-month pilot project in Nanchang district in southeastern Jiangxi province in May 2005, the government persuaded farmers in three villages to give up some 1,000 working cattle in exchange for tractors and cash. Researchers used rats to test the prevalence of the parasite before and after the project and results were encouraging. "We put rats in the water at the start of the project and 27 percent of them became infected after 10 seconds. We did the same thing at the end of the project and found that the infection rate fell to 0.2 percent," Hao said. "We intend to implement this (removing working cattle) in affected provinces in the coming years," he said. But he conceded that it would be difficult to persuade farmers to exchange their animals for machines. "I think we won't see the end to this problem in our lifetime," he said. Some 207 million people worldwide have the disease.
