According to the Chinese media, 87 people are now infected with meningitis after eating undercooked snails at a Beijing restaurant.
They have been diagnosed with a type of angiostrongyliasis, a disease caused by parasites that affects the brain and spinal cord, which can lead to meningitis.
Most became sick after eating raw or half-cooked Amazonian snails contaminated with parasites at a restaurant specializing in Sichuan-style cooking.
The Tropical Diseases Department of the Beijing Friendship Hospital, which specializes in treating the disease, has opened three more clinics and extended consultations, with each doctor seeing nearly 100 people a day, and they still apparently cannot cope with the numbers who believe they have the disease.
Sixteen have been hospitalised and are in a critical condition.
Chinese authorities have traced the problem to the Shuguo Yanyi Restaurant which has made an official apology to customers and is cooperating with the Beijing Health Bureau in the investigation.
The restaurant is prepared to compensate those who fell ill after eating the snails.
According to the Beijing Health Bureau, treatment for each patient will cost at least 3,000 yuan (U.S. $375).
The patients range in age from 13 to 51 years old and all ate raw or undercooked Amazonian snails two to four weeks ago in outlets of the Shuguo Yanyi Restaurant.
Tests on snails taken from the restaurant found several infected with a meningitis-causing parasite.
The disease can have lon-lasting effects such as headaches and dementia, and health authorities say on-going medical treatment will be needed to ensure the patients' complete recovery.
The Beijing Health Bureau said the infection was caused by processing problems at the restaurant, which did not eradicate eel worms in the snails.
All agricultural markets, supermarkets, department stores and restaurants are banned from buying, selling and processing the Amazonian snails.
As it can take two to four weeks for symptoms to appear the link between the illness and eating a raw snail may not be obvious.
The large, black Amazonian snails originated in South America and were first brought to China in the 1980s as a delicacy.
They have since become widespread, breeding very rapidly in lakes, streams and ponds across the country.
The snails are a popular dish in big Chinese cities such as Beijing but the very same species is responsible for decimating large areas of farmland in the south of China where more than 160,000 hectares of crops have been destroyed in the Guangxi Zhuang region.
The first patient to fall ill after eating the snails was reported in Guangzhou, capital city of south China's Guangdong Province.