The infection rate of food-borne parasitic diseases has risen dramatically in the country in the past 10 years, health officials said Monday.

In particular, incidences of liver fluke infections, a prevalent food-borne parasitic worm, has increased by 75 percent over the same period, according to a survey conducted by the Ministry of Health throughout China's 31 provinces and autonomous regions from June 2001 to 2004.

It is estimated that more than 12 million Chinese have been infected with liver fluke through food, and have gone on to develop hepatic distomiasis, a liver disorder.

South China's Guangdong Province, the Guangxi Zhuang Autonomous Region and northeast China's Jilin Province have the highest rates of hepatic distomiasis, recording a 182, 164 and 630 percent increase respectively compared with a similar survey conducted from 1988 to 1990. Guangdong is home to almost half of the nation's hepatic distomiasis patients.

"Food-borne parasitic disease is a growing threat to public health and an outstanding issue for food safety," said Hao Yang, an official with the Health Ministry's Disease Control and Prevention Division.

The survey attributed the increasing incidence of liver fluke-induced diseases to people's growing penchant for raw food.

More and more people have developed a taste for raw seafood, especially those living in coastal regions. For example, raw fish salad, a kind of sashimi, is a common food for people living on the coast.

Liver fluke found in seafood can cause severe distomiasis in human beings, said Xu Longqi, a researcher with the National Institute of Parasitic Disease under the Chinese Center for Disease Control and Prevention.

Symptoms of the disease include diarrhea and liver cirrhosis, he added.

Eating raw or semi-raw pork and beef can also trigger the spread of parasitic diseases, as has been proven by the high rates of infections in southwest China's Yunnan Province, where such food is popular.

Local residents in Dali and Simao in Yunnan, for example, enjoy eating raw pork, which provokes infection, said Xu.

However, land-borne parasitic diseases that infect human beings are well under control, said Hao.

On a national level, the infection rate of this kind of parasitic disease is 63.65 percent lower than that for food-borne diseases.

In 1990, there were 536 million patients with nematodiasis. By the end of 2004, this figure had dropped to 136 million.

Incidences of hookworm, roundworm and whipworm, the more common land-borne parasitic diseases, are in sharp decline, said Xu.

"Rural hygiene campaigns have helped eliminate the worms, and lower the infection rate," said Hao.

(China Daily May 17, 2005)