Fast spread of swine flu raises alarm

As Mexico struggled to contain a strange new strain of swine flu that has killed as many as 81, international health officials warned of a possible public-health emergency. More cases developed in the U.S.

"It has pandemic potential," Margaret Chan, the director-general of the World Health Organization, told reporters yesterday. "It is infecting people."

The number of confirmed cases of the virulent strain in the U.S. spread outside the Southwest, and Virginia health officials yesterday alerted health-care providers to watch for the strain among people with flu-like symptoms. There have been at least 11 cases in the U.S., but no cases reported in Virginia and no deaths.

The WHO yesterday asked countries around the world to step up reporting and surveillance of the disease and implement a coordinated response to contain it.

But Mexicans were dying for weeks at least before U.S. scientists identified the strain -- a combination of swine, bird and human influenza that people may have no natural immunity to. Now, even controlling passengers at airports and bus stations may not keep it from spreading, epidemiologists say.

The disease, which is believed to have sickened more than 1,000 in Mexico, has already reached Texas, California, Kansas and probably New York. Two dozen new suspected cases were reported yesterday in Mexico City alone, where authorities suspended schools and all public events until further notice. More than 500 concerts, sporting events and other gatherings were canceled in the metropolis of 20 million.

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.

Officials said the decree gives clear legal authority to Health Department workers who might otherwise face reprisals.

Health workers and soldiers joined a broad effort at airports and bus stations to keep people with the disease from traveling though or out of the city. But with confirmed swine flu cases in at least six Mexican states -- and possibly as many as 14 -- the efforts seemed unlikely to stop the spread of the disease.

Airports around the world were screening travelers from Mexico for flu symptoms. But containing the disease may not be an option given the number of cases spread across Mexico.

"Anything that would be about containing it right now would purely be a political move," said Michael Osterholm, a University of Minnesota pandemic expert.

The Kansas Department of Health and Environment yesterday confirmed two cases of swine flu in two adults in the same household. One of the patients had recently traveled to Mexico. Another eight students at a New York City high school probably have human swine influenza, but health officials said they don't know for sure whether it is the same strain.

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

An emergency meeting of special experts was convened yesterday at WHO headquarters in Geneva to decide what steps should be taken to contain the virus. It is the first time the committee has been called upon since it was created two years ago to handle disease outbreaks.

The WHO held off on raising its pandemic alert level, citing the need for more information.

Scientists have warned for years about the potential for a pandemic from viruses that mix genetic material from humans and animals.

Also worrisome is that authorities said the dead so far don't include vulnerable infants and elderly. The Spanish flu pandemic, which killed at least 40 million people worldwide in 1918-19, also first struck otherwise healthy young adults.

This swine flu and regular flu can have similar symptoms -- mostly fever, cough and sore throat, though some of the U.S. victims who recovered also experienced vomiting and diarrhea. But unlike regular flu, humans don't have natural immunity to a virus that includes animal genes -- and new vaccines can take months to bring into use.

While stressing there had been no swine-flu cases reported in the state, the Virginia Department of Health yesterday said it was urging health-care providers to have a "high index of suspicion" regarding cases of influenza-like illness.

"We are contacting health-care providers in the state, alerting them of the situation and asking them to test individuals who have flu-like symptoms and have traveled to affected areas up to seven days before becoming ill," said Virginia Health Commissioner Karen Remley.