Although the pace of new H1N1 infections seemingly slowed yesterday — with a total of 195 cases now reported in the United States and 793 worldwide, and a few even turning up in pigs — a World Health Organization official said he thought the agency's infectious disease alert level ultimately would be raised to its highest point.

"At the present time, I would still propose that a pandemic is imminent because we are seeing the disease spread," Michael Ryan, the agency's director of global alert and response, said in a Geneva news conference.

"We have to expect that Phase 6 will be reached; we have to hope that it is not," he said.

The level will be raised when the agency sees evidence of sustained person-to-person transmission of the virus outside North America. So far, he emphasized, that has not occurred, except in a handful of cases.

On Monday, the agency raised the alert level to Phase 4 from the normal Phase 3, a sign that a pandemic was imminent or inevitable.

That increase had little effect on industrialized countries, which were making extensive preparations to combat an outbreak of the disease, unofficially known as swine flu. But it was viewed as a wake-up call to less-developed countries to increase their planning.

On Wednesday, WHO raised the alert to Phase 5.

Ryan said the WHO would send 72 developing countries 2.4 million courses of the antiviral agent Tamiflu from its emergency stockpile. The drug's manufacturer, Roche, said it would send an additional 3 million doses and that it was scaling up production of the drug.

The latest U.S. count includes six new cases in California, bringing the total to 24. The count also includes 12 new cases in New York, two in Florida, and one each in Connecticut, Missouri, Utah, New Hampshire and Rhode Island, the first cases in those states.

Ryan said about one-third of U.S. cases resulted from visits to Mexico. The rest contracted it through human-to-human transmission.

Worldwide, Italy, Ireland and Costa Rica confirmed their first H1N1 cases.

Canadian officials also said yesterday they had confirmed the presence of the H1N1 virus in a small herd of pigs in Alberta and that the pigs had been quarantined. It marked the first time the new virus has been discovered in animals; officials believe the pigs were infected by a farmworker who visited Mexico and fell ill after returning home. Both farmer and pigs were recovering.

The number of confirmed dead in Mexico stood at 19 yesterday, Health Secretary Jose Angel Cordova said at a news conference in Mexico City. Cordova also said the outbreak there might not be as serious as originally suspected: Out of more than 1,000 suspect cases, he said, only 473 cases were confirmed to be H1N1.

"It would still be imprudent to say that we're past the worst of it, but I do think ... we are in a stage of stabilization," he said.