This sober message came one day after news was released of a Hong Kong man in Tin Shui Wai who came down with the swine bacteria and was admitted to hospital July 5. The man had not visited the mainland recently and did not handle pork in his work.

There have been three other local cases in the last two months, according to the Centre for Health Protection.

Regina Ching, acting director of the CHP, said the streptococcus suis bacteria that is associated with the disease outbreak and is common in pigs, is more active in summer, when the warm weather can promote its spread.

``The bacteria infiltrate the pigs' blood and then humans can be infected after contact with pigs,'' Ching said.

Health authorities are tracing the source of the infections that have surfaced in Hong Kong, Ching said.

A three-member Hong Kong expert team was in Sichuan Friday, where it visited a hospital and conducted interviews with a number of patients.

Ten people- all male-have been stricken by the disease in Hong Kong since last May. One person died and the rest recovered.

Ching played down fears that the disease is spreading faster than in previous years. She said the infection might be confined to males because men have poorer hygiene.

``As we all know, housewives are also exposed to pork, yet none of the patients is female,'' she said. ``I anticipate men who are occupationally exposed to pigs may not be aware that a minor skin injury can lead to infection.''

Sichuan, the country's top pork-producing province, was forced to suspend all exports of chilled and frozen pork from Ziyang and Neijiang this week.

Meanwhile, Beijing and several other cities set up checkpoints Friday to block the disease as authorities ordered a halt to the slaughter of infected pigs in Sichuan province.

More than 50,000 health workers and officials have been sent to the Ziyang area to inspect and register every pig and set up 39 temporary roadside quarantine stations to stop dead pigs from going to market, the China Daily said.

The World Heath Organization said Friday it agreed with China's Health Minister Gao Qiang that preliminary steps have been taken to control the disease - but the battle is far from over.

WHO spokesman Bob Dietz said it is too soon to declare the epidemic contained because there are new cases and new deaths. ``More is needed to be done to control the spread of this disease,'' said Dietz. He insisted that the WHO and Chinese authorities agree on the course to take to contain the epidemic.

The WHO said more investigations, including laboratory tests, are needed to see if other factors might be at work.

``Previously unknown cases have been found because disease-control experts have intensified their surveillance and examinations of affected areas,'' Gao said on state television Friday. ``The increase in cases does not mean there are new infections. The people may have been infected in the past and not been found or reported.''