Posted: Apr. 25, 2009

Mexico's president assumed new powers Saturday to isolate people infected with a deadly swine flu strain as authorities struggled to contain an outbreak that world health officials are warning could become a global epidemic.

New cases of swine flu were confirmed in Kansas and California and suspected in New York City, but health officials said they didn't know whether it was the strain that has killed as many as 81 people in Mexico and likely sickened at least 1,324. No cases have been confirmed in Wisconsin.

Mexican soldiers and health workers patrolled airports and bus stations as they tried to corral people who may be infected with the swine flu, as it became clearer that the government may have been slow to respond to the outbreak in March and early April.

Now, even detaining the ill may not keep the strain - a combination of swine, bird and human influenza to which people may have no natural immunity - from spreading, epidemiologists say. Scientists have warned for years about the potential for a pandemic from viruses that mix genetic material from humans and animals.

The World Health Organization on Saturday declared the outbreak of the previously unknown virus "a public health emergency of international concern" and asked countries to step up surveillance of the disease and implement a coordinated response to contain it.

Two dozen new suspected cases were reported in Mexico City alone, where authorities suspended schools and all public events until at least May 6. More than 500 concerts, sporting events and other gatherings were canceled in the metropolis of 20 million.

Hospitals dealt with crowds of people seeking help. A hotline fielded 2,366 calls in its first hours from frightened city residents who suspected they might have the disease.

Doctors reported that anti-viral medications and even steroids were working well against the disease, noting no new deaths had been reported in the capital in the last day.

Wisconsin has no confirmed cases of swine flu, Wisconsin Department of Health Services spokesman Seth Boffeli said Saturday.

The department sent an update Friday to all public health agencies and physicians across the state, telling them what symptoms to look for and what guidelines to follow if they suspect they have a case -including how to handle a sample. No samples are known to have been submitted, Boffeli said.

"We want to make sure our reporting system is as beefed up as it can be," he said.

The Mexican government issued a decree authorizing President Felipe Calderon to invoke special powers, letting the Health Department isolate patients and inspect homes, incoming travelers and baggage.

The White House said Saturday that President Barack Obama's health is fine a little more than a week after he traveled to Mexico to meet with top government officials and talk about drug smuggling and border violence.

Obama is being updated regularly on the swine flu outbreak, with the Homeland Security Council monitoring the situation along with the State Department and the U.S. Centers for Disease Control and Prevention.

At Mexico City's international airport, health workers passed out written questionnaires seeking to identify passengers with flu symptoms. Surgical masks and brochures were handed out at bus and subway stations. The U.S. Embassy in Mexico posted a message advising U.S. citizens to avoid large crowds, shaking hands, greeting people with a kiss or using the subway.

But with confirmed swine flu cases in at least six Mexican states (Mexico City, Mexico State, Veracruz, Oaxaca, Baja California and San Luis Potosi) - and possibly as many as 14 - the efforts seemed unlikely to stop the spread of the disease.

Particularly difficult in a metropolis as crowded as Mexico City was the embassy's advice that maintaining "a distance of at least 6 feet from other persons may decrease the risk of exposure."

WHO Director-General Margaret Chan said the outbreak of the never-before-seen virus has "pandemic potential." But she said it is still too early to tell if it would become a pandemic.

"The situation is evolving quickly," Chan said in Geneva. "A new disease is by definition poorly understood."

WHO lays out three criteria necessary for a global epidemic to occur: The virus is able to infect people, can readily spread person-to-person, and the global population has no immunity to it. The agency held off raising its pandemic alert level, citing the need for more information.

Early detection and treatment are key to stopping any outbreak. WHO guidance calls for isolating the sick and blanketing everyone around them with anti-viral drugs such as Tamiflu.

Now, with patients showing up all across Mexico and its teeming capital, simple math suggests that kind of response is impossible.

Mexico appears to have lost valuable days or weeks in detecting the new virus. Health authorities started noticing a threefold spike in flu cases in late March and early April, but they thought it was a late rebound in the December-February flu season.

Testing at domestic labs did not alert doctors to the new strain, although U.S. authorities detected an outbreak in California and Texas last week.

Perhaps spurred by the U.S. discoveries, Mexico sent 14 mucus samples to the CDC on April 18 and dispatched health teams to hospitals looking for patients with severe flu or pneumonia-like symptoms.

Those teams noticed something strange: The flu in Mexico was killing people ages 20 to 40. Flu victims are usually either infants or the elderly. The Spanish flu pandemic, which killed at least 40 million people worldwide in 1918-'19, also first struck otherwise healthy young adults.

On Thursday, Mexico City Health Secretary Armando Ahued said, officials got a call "from the United States and Canada, the most important laboratories in the field, telling us this was a new virus."