A mysterious pig-borne disease has spread to six more towns in southwest China and the number of people killed has risen to 31, the Chinese government said yesterday as it scrambled to reassure the public.
The health ministry said on its Web site that the total number of people affected increased to 152 by noon on Wednesday -- four more deaths and 21 more cases than the day before. Twenty-one people are in critical condition.
Six more towns in Sichuan Province reported cases on Wednesday, in addition to the two cities, Ziyang and Neijiang, where people first fell ill after slaughtering pigs foaming at the mouth last month, the ministry said.
The World Health Organization (WHO) said it was baffled.
It said if the disease was indeed caused by the streptococcus suis bacterium, as preliminary Chinese results show, it would be the first time the bacterium had struck so many people at one time -- raising fears it had become more virulent.
The Chinese government was working to reassure the public that it had the problem under control, stressing the spread could be stopped if people avoided slaughtering infected pigs.
"We have the technology and procedures to bring the disease under control," the China Daily quoted an agriculture ministry official as saying.
Investigations show that only those who came in contact with infected pigs or pork -- through slaughtering or processing -- and had open wounds fell ill, the Beijing Daily Messenger cited experts as saying.
Those who only ate the cooked pork did not get sick, it said.
The victims were mostly farmers who raised pigs in small, insanitary farms. Farmers said they had a habit of eating sick pigs instead of burying them because they were poor.
Newspaper accounts said many people pitched in to shave the hair off the killed swine, wash the internal organs and chop up the meat to distribute.
One woman who fell ill was quoted by the Beijing Daily Messenger as saying that she did not think anything of the small wound on her hand when she helped a relative kill a pig last week.
"After killing the pig, our entire family boiled three bowls of pork to eat. After eating just a few mouthfuls of the meat, I felt my heart pound, dizzy and nauseous," Jiang Suhua said. "Later my legs were so weak I couldn't stand up. My arms and legs also had large blotches of blood under the skin."
Another farmer said that a relative gave him a slice of freshly cut pork and he became dizzy and weak just from taking the pork home.
Other symptoms include high fever, vomiting and hemorrhaging, with many patients going into severe shock. Some of the victims died within 10 hours of showing symptoms, reports said.
The disease is rare, with the first recorded case in Denmark in 1968. More than 200 cases of human infection have been reported since then, not counting the latest data.
WHO spokesman Bob Dietz said it was too soon to say the bacterium was the cause or the only cause of the outbreak, adding that more laboratory tests were needed to see if other factors may be at work.
"We can't discount the possibility there could be other bacteria, virus or something else active in here," Dietz said.
The bacterium is endemic in Asia, North America and Europe, he said.
If it is the cause of the outbreak, the Chinese farmers' close proximity to their pigs might be a reason for the large number of cases.