Disease watchdogs in northeast China's Heilongjiang Province yesterday warned people
not to eat raw freshwater products in order to avoid the
parasite-caused disease clonorchiasis.
A recent survey by the Heilongjiang Provincial Centre for
Disease Control and Prevention estimated that more than 1.5 million
people living near rivers in the province might have the disease,
said Ji Zhuo, director of the parasite disease institute at the
The overall incidence of clonorchiasis in the province is about
4.7 percent, which means more than 1.5 million people out of a
population of 38 million may have the disease, Ji said. A reason
for the huge number could be that more people are in the habit of
eating raw aquatic products, he added.
The news comes as medical authorities nationwide warned about
the danger of eating raw or undercooked freshwater seafood to
prevent diseases caused by parasites.
The warning came after 70 people in Beijing were found to be
suffering from meningitis after eating the Amazonian snail. Many
said they might sue for compensation.
Improper cooking or the eating of raw snails, which failed to
kill the Angiostrongylus cantonesis, a parasite in the snail, were
believed to have caused the disease in the capital.
Ji in Heilongjiang said spot checks showed a higher percentage
of clonorchiasis in some places.
The province's Zhaoyuan County, where two major rivers meet, had
the highest incidence of the disease.
Five hundred people were picked at random; about 200 were found
to be infected with the parasite.
"Even allowing for errors, the rate is still about 30-40
percent," Ji added. "And even if we go with 30 percent, that still
means 120,000 people out of the 400,000-plus people in Zhaoyuan may
have been infected," Ji said.
In humans, the parasite lives in the duct connecting the liver
and bile cyst.
Preliminary symptoms of the disease are vomiting, fatigue and
aching. In severe cases, liver cancer and other serious conditions
"Some people may feel uncomfortable immediately while some may
find the disease 10 or 20 years later, when it is too late," said
Ji, adding that more than 10,000 of the parasite's spawn were found
in one man.
Ji suggested that people who have eaten raw or undercooked
freshwater products get a medical check as soon as possible.
He said more people were getting the disease "mainly because
more people have begun to eat raw fish."
Nationwide, clonorchiasis is listed as one of the key
parasite-caused diseases in China. In 2004 the government estimated
that more than 12 million people could be affected.
The Pearl River Delta and northeast China are the two major
areas for it.
An estimated 5 million people in Guangdong were reported by
local media to have the disease last year.
Meanwhile, in Beijing, hospitalized patients diagnosed with
meningitis after eating parasite-infested snails in a Beijing
restaurant said they might sue for compensation.
The Xinhua News Agency quoted a patient surnamed Zhang as saying
he had spent 20,000 yuan (US$ 2,500) on treatment.
"Patients have discussed jointly making a claim for medical
expenses and compensation for lost work and emotional suffering,"
(China Daily August 23, 2006)