The death toll in an outbreak of pig-borne disease in the southwest Chinese province of Sichuan has risen to 24, with another 117 thought be sick, state media reported on Wednesday.

Victims were being treated with antibiotics, but with the death toll mounting doctors said that approach was unsatisfactory.

“The Chinese Centre for Disease Control and Prevention is conducting drug sensitivity tests to find a more effective treatment,” the newspaper quoted Health Ministry spokesman Mao Qun’an as saying.

Laboratory tests showed the affected people were suffering from Streptococcus suis infections contracted from the slaughtering or handling of infected pigs.

The bacteria is endemic in swine in most pig-rearing countries in the world but human infections are rare. Although state media has said no human-to-human infections had been found in the Sichuan outbreak, the death toll is unusually high.

The Sichuan mortality rate stands at 17 percent so far, higher than the usual 10 percent, experts in Hong Kong said.

The disease can be prevented if people refrain from slaughtering, processing or eating infected pigs, the China Daily quoted Chen Huanchun, vice-president of Huazhong Agricultural University as saying.

China was also working on a vaccine to protect pigs from the disease, he said.

Sichuan authorities suspended exports of chilled and frozen pork to Hong Kong on Tuesday, a Hong Kong government spokeswoman said. The city imported 30,000 tonnes of chilled and frozen pork from Sichuan last year.

Initially, 20 farm workers suffered fever, nausea and haemorrhaging after handling sick or dead pigs and sheep in 12 towns and 15 villages in Sichuan province. More cases were reported as health workers combed villages for ill people.

The Chinese government has launched campaigns to slaughter infected pigs and investigate small farms with poor sanitation standards, state media has said.

Pork prices in the affected Ziyang area of Sichuan have dropped 20 percent, the newspaper said, and farmers were worried their pigs would not survive the epidemic.

“If they die, it would mean a loss of 2,400 yuan ($296),” farmer Wang Jian was quoted as saying, adding that was about one-quarter of his family’s annual income.

The government of Sichuan earlier dismissed speculation that the deaths were caused by bird flu or severe acute respiratory syndrome (SARS), an assessment affirmed by the World Health Organisation.

Global health officials have been on high alert over a bird flu virus that has killed over 50 people in Asia since late 2003.

SARS emerged in south China in 2002 and spread across 30 countries, infecting nearly 8,500 people and killing about 800.