Health officials said yesterday that they have yet to find specific treatments for people infected with a disease that has killed 24 farmers in the southwestern province of Sichuan.

At the moment doctors are relying on heavy doses of antibiotics to treat patients, but with the death toll mounting the pressure is on to find a better therapy.

"The Center for Disease Control and Prevention is conducting drug sensitivity tests to find a more effective treatment," said Ministry of Health spokesperson Mao Qun'an, and daily reports on the situation have been made to the WHO.

The ministry said the outbreak was caused by Streptococcus suis, a bacteria carried by pigs, and the first patient was hospitalized on June 24 in Ziyang No.3 People’s Hospital.

The number of human cases has risen to 117 in two neighboring cities, Ziyang and Neijiang. Of these, 76 infections are confirmed and 41 suspected, with 21 in a critical condition.

Chen Huanchun, vice president of Hubei Province’s Huazhong Agricultural University, said pig-to-human infection can be prevented if people refrain from slaughtering, processing or eating infected pigs.

Chen, also a member of the expert group set up by the Ministry of Agriculture to conduct on-the-spot investigations, said the bacteria can only infect people through open wounds or if they digest infected meat.

Pork prices have dropped 20 percent in Ziyang, said Cao Jingli, a government employee there.

Chen said the Guangzhou Veterinary Medicine Plant is working on a vaccine to protect pigs from the disease, expected to take about a week, and it will be used after a two-to-three-day safety test.

The infected farmers and pigs are scattered throughout 73 villages around Ziyang and Neijiang. So far no cases have been reported elsewhere.

Expert investigators said poor sanitary conditions had been found on the 300-plus farms where the pigs were raised, and the provincial government said no infected pigs have been found on large- or medium-sized breeding farms.

Experts said they are searching for the reason for the outbreak since many healthy pigs ordinarily carry the bacteria but do not fall ill or transmit the disease.

In the two affected cities, all 469 pigs with the disease have been buried and 50 temporary checkpoints set up to stop pigs from being transported from infected villages.

Wang Jian, a 41-year-old farmer in Panshi Village in Danshan Town of Ziyang, is worried that his four pigs will not survive the epidemic.

"If they die, it would mean a loss of 2,400 yuan (US$296), one-quarter of my family's annual income," he said.

More than 50 pigs in his village have died from the disease.

(China Daily July 27, 2005)