The number of people confirmed to have fallen ill after eating raw or half-cooked snails contaminated with parasites at a Beijing restaurant has risen from 70 to 87, the Beijing Health Bureau reported on Wednesday.

A patient suffering from meningtis after eating snails recevies treatment at a hospital in Beijing, August 20, 2006. [Beijing Star Daily]

They were diagnosed with a type of angiostrongyliasis, a disease caused by parasites that affects the brain and spinal cord, and can lead to meningitis, the bureau said.

In the past few days, the Tropical Diseases Department of the Beijing Friendship Hospital, which specializes in treating the disease, has been crowded with people who have headaches or stiff necks, including some people who hadn't even eaten raw or half-cooked snails or other river or seafood.

The hospital has opened three more clinics and extended consultations, with each doctor seeing nearly 100 people a day, but they still cannot meet the demand, a hospital spokesman said.

After two to three weeks' treatment, most of the first group of patients the Friendship Hospital received are now in a stable condition, and some of them will be discharged from hospital this week, the spokesman said.

Because the disease may produce sequelae such as headaches and dementia, the hospital will follow up the medical treatment to ensure the patients' complete recovery, he said.

Dr. Yin Chenghong, an expert with the hospital's Tropical Medicine Institute, warned citizens not to panic, saying that if they hadn't eaten raw or half-cooked snails or other aquatic food, they wouldn't fall prey to the disease.

"There's no need for the public to panic, they had better go to a clinic first if they have fever or a headache," he said.

The Friendship Hospital's first case of meningitis occurred on June 24 when a 34-year-old man was admitted suffering from a violent headache and nausea after eating a dish of cold snail meat at an outlet of the Shuguo Yanyi Restaurant.

The Shuguo Yanyi Restaurant that sold parasite-contaminated snails made an official apology to customers on Wednesday.

Qu Chuangang, spokesman for the Shuguoyanyi Restaurant, which serves Sichuan-style food, said they will assume responsibility for the incident and try their best to deal with the problems caused.

"All the 390 staff members of our restaurant feel deeply sorry about the incident. We hope we can do something to make up for it, " said Qu.

The restaurant admitted that the snails had not been processed correctly, which was the main reason customers had fallen sick.

The restaurant has formed a team to cooperate with the Beijing Health Bureau in the investigation.

The spokesman said his restaurant is ready to compensate those who fell ill after eating the snails.

He said patients can bring them their restaurant bill and those who do not have a restaurant bill can also be compensated because Shuguoyanyi can confirm their visit by tracking dining records.

According to the Beijing Health Bureau, treatment for each patient will cost at least 3,000 yuan (about 375 U.S. dollars).

A patient surnamed Zhang said that he has spent 20,000 yuan (2,500 U.S. dollars) on medical treatment. He wants compensation for physical and mental suffering.

To date, no deaths have been reported.

Among the patients, the youngest was 13 years old and the oldest 51. All the patients ate raw or undercooked Amazonian snails two to four weeks ago in outlets of the Shuguo Yanyi Restaurant, according to the Beijing Health Bureau.

The bureau confirmed in its earlier report that the infection was caused by processing problems in the restaurant, which failed to eradicate eel worms on the snails.

The restaurant was ordered to stop selling the snail dishes on August 8.

The Beijing health monitoring department posted an urgent notice on Monday, asking all the restaurants in the city to stop providing the customers with any undercooked snails.

The municipal food safety office ordered on Tuesday that all the agricultural markets, supermarkets, department stores and restaurants must stop buying, selling and processing the Amazonian snails.

Many Beijing citizens are sending text messages to their friends or family members, warning them against the disease-caused food.

Yet Yin Quanxi, director of the emergency center of the Beijing health monitoring department, said the snails are still edible after they are cooked under the temperature above 90 Celsius degrees for more than two minutes.

The health bureau is trying to trace the suppliers of the snails contaminated with eel worms.

The bureau also demanded the city's disease control and health monitoring departments, together with the restaurant, make reports upon the infectious cases every day.

Amazonian snails originated in South America and first came to China in the 1980s as a delicacy. The first patient to fall ill after eating the snails was reported in Guangzhou, capital city of south China's Guangdong Province.

The large, black snails were a hot-selling aquatic product in big Chinese cities like Beijing.