Swine Flu Outbreak Not a Pandemic, Yet

May 3 -- SUNDAY, May 3 (HealthDay News) -- Although the number of swine flu cases continued to climb Sunday, the World Health Organization said there is no clear sign yet that the scope of the outbreak has reached pandemic proportions.

That doesn't mean it won't, however.

"At the present time, I would still propose that a pandemic is imminent because we are seeing transmission to other countries," Dr. Michael J. Ryan, director of the World Health Organization (WHO) global alert and response team, said in a teleconference from Geneva on Sunday. "We have to expect that Phase 6 will be reached. We have to hope that it is not."

As of Sunday morning, the WHO Web site was reporting 787 confirmed cases of swine flu in 17 countries. Mexico has reported 506 cases, with 19 deaths, while the United States has confirmed 160 cases in 21 states.

Currently, the outbreak is gauged a Level 5, meaning the disease is spreading throughout communities in at least two countries in one of WHO's six regions, in this case the United States and Mexico. To reach Phase 6, the geographic spread of the disease would have to occur in at least one other country in another region.

In a strange twist on Saturday, swine flu was discovered for the first time in pigs. WHO officials reported on the organization's Web site that the virus had been detected in sick pigs on a farm in Alberta, Canada. Until now, it was not known whether the virus could infect pigs, even though its genetic makeup clearly points to its having originated in that animal. However, in this case a human appears to have infected the livestock, not the other way around, the WHO reported. A worker on the farm had traveled to Mexico, come back to Canada and fallen ill. The swine are now under quarantine. WHO officials stressed that the swine flu cannot be transmitted through the consumption of pork products.

And the swine flu continued to spread across the United States on Saturday, as federal health officials reported there are now 160 confirmed cases in 21 states, with 13 hospitalizations and one death.

"We have information that this novel virus continues to spread with increasing cases and increased states affected, and we are acting actively and aggressively. Our highest priority is the health and safety of the American public," Dr. Anne Schuchat, interim deputy director for the science and public health program at the U.S. Centers for Disease Control and Prevention, said during a teleconference Saturday. "We have seen times when things appear to be getting better and then get worse again. With a new virus like this, we don't know how it's going to behave or change over time."

Since schools are the focus of many of the outbreaks, the CDC has issued new recommendations for school closings.

Because children may shed the virus longer than adults, the agency is now recommending that affected schools remain closed for two weeks instead of one, Schuchat noted. However, what individual communities decide to do is up to them and their own analysis of the situation, she added.

The U.S. Education Department said Friday that more than 430 schools had closed, affecting about 245,000 children, the Wall Street Journal reported.

Nancy Cox, chief of the influenza division of the National Center for Immunization and Respiratory Diseases at the CDC, did deliver some welcome news on the nature of the virus itself on Friday. She said during a teleconference that a preliminary analysis of the H1N1 strain finds it lacks certain "virulent characteristics" that made the 1918 flu pandemic strain so deadly.

And the new Secretary of Health and Human Services, Kathleen Sebelius, has made the decision to buy 13 million more courses of antivirals to replenish the antiviral stockpile, Schuchat said. "We don't know if we are going to need them, we just wanted to be ready," she said.

In addition, the United States has shipped 400,000 regimens of antivirals to Mexico, believed to be the source of the global outbreak, at the request of the Mexican government, Schuchat added.

Meanwhile, President Barack Obama has urged Americans to stay calm, noting that it was not clear whether the global outbreak of the never-before-seen flu strain was any worse than "ordinary flus." But, he added, agencies across the U.S. government are preparing for the worst, according to the AP.

(As of May 2, 2009, 11:00 AM ET)