Dark water: Deadly fever lurks in a Chinese lake

The parasites travel through the bloodstream before eventually attacking the liver, pancreas and stomach. People are often slow to realise they are infected, and chronic patients can suffer lethargy, high fevers, swollen stomachs and, in some cases, death.

‘‘It’s a downward spiral that can be slow and quite painful,’’ said Dr. Jeffrey Gilbert, an infectious diseases specialist with the World Health Organisation in Beijing, who in late February will lead a fact-finding mission to assess the problem.

Liao stood outside her l house and described how illness had steadily consumed her body over eight years. Her stomach was swollen with fluid. Her joints ached. ‘‘I have no money, I have no plan,’’ she said that day late last year. By last month, her relatives later relayed said, she was dead.

For people in northern Hunan province, many of them farmers and fishermen, the thought of not touching the water is almost as difficult as not breathing the air.

So in villages behind the levees along Dongting Lake, the infection rates for snail fever, which had been thought to be eradicated during the 1950s, reach as high as 80 per cent. Nationally, nearly 900,000 people have the disease and an estimated 30 million people are at risk.