Also on Friday, one more person was killed by the bacteria, which is carried by pigs, bringing the total death toll to 32.

The five new sites where infections have been found are: provincial capital Chengdu, Zigong, Suining, Luzhou, and Mianyang. Twenty-five cases were identified in the five cities in the past three days.

Since the outbreak started on June 24, official reports have previously only identified Ziyang and Neijiang as the affected places.

The Ministry of Health said the new cases were discovered as a result of the local health authorities' strengthened publicity efforts and were not necessarily new infections.

Chen Nenggang, deputy mayor of Ziyang, said the city has issued more than 2 million posters urging farmers not to slaughter or eat sick pigs.

By noon on Friday, 163 confirmed human cases of the disease in Sichuan had resulted in 32 deaths, 24 patients were in a serious condition.

Thanks to increased publicity, most farmers are aware of the grave consequences of butchering or eating dead or sick pigs, said Li Jing, chief of the publicity department of the Ziyang Party committee.

On Wednesday, three reporters from a Hong Kong television station paid a farmer in Ziyang 40 yuan (US$4.9) to dig up a pig that had died of the disease.

"They took pictures of the pig to show what an infected pig looked like. But they violated the quarantine law as digging the pig up could spread the disease," Li said. Fortunately, local health and quarantine officials quickly put a stop to the exhumation.

Meanwhile, four local officials in Ziyang have been removed from their posts on the grounds of dereliction of duty.

In Dongfeng Town, Party head Wei Guicheng and Yang Kaiming, the town's deputy chief, were removed from their posts after they failed to prevent a farmer from butchering sick pigs. The farmer is still in hospital.

In Qingfeng town, quarantine official Pan Dinggang was sacked because he allowed pigs to be transported outside an affected village. Name and location of the fourth official were not disclosed.

Health Minister Gao Qiang went to Neijiang from Ziyang on Friday. He asked local health authorities to provide prompt medical treatment to every patient. He also asked medical workers to visit every villager to provide them with medical support.

In Beijing, Minister of Agriculture Du Qinglin asked provinces and municipalities, especially those bordering the infected regions, to ensure contingency plans are in place.