MEXICO CITY — The World Health Organization rushed to convene an emergency meeting Saturday to develop a response to the “pandemic potential” of a new swine-flu virus that has sparked a deadly outbreak in Mexico and spread to the United States.
Health officials reported that at least eight students at a private high school in New York had “probable” swine flu. They also confirmed three new cases — two in Kansas and one in California — bringing the total number of confirmed U.S. cases to 11.
The president of Mexico, where the outbreak has killed as many as 81 people, issued an order granting his government broad powers to isolate patients and question travelers.
“This is a serious moment for the nation,” President Felipe Calderon said Saturday. “And we are confronting it with seriousness, with all the pertinent measures.”
The director general of the World Health Organization, Margaret Chan, said the “situation is evolving quickly.”
“We do not yet have a complete picture of the epidemiology or the risk, including possible spread beyond the currently affected areas,” Chan said
The WHO, after the 15-member emergency committee met for about two hours, described the outbreak as a “public-health emergency of international concern” and recommended countries intensify their efforts to identify “unusual outbreaks of influenza-like illness and severe pneumonia.”
“In the assessment of the WHO, this is a serious situation that must be watched very carefully,” Chan said. “It has pandemic potential.”
Chan stressed that a pandemic was not underway or inevitable and noted that no outbreaks have been reported elsewhere.
The virus, for which there is no vaccine for humans, nearly brought Mexico City to a halt. Normally congested downtown streets in this city of 20 million were almost empty Saturday.
Soldiers posted at subway stations handed out face masks to passers-by from the back of armored vehicles. Some pedestrians covered their mouths and noses with scarves and rags.
“We can’t escape the air,” said Antonio Gonzales, 56, who wore a surgical mask outside a hospital. “If it was something in the food, we’d have a chance.”
The Mexican government said more than 1,000 people might be infected with the virus, which is a combination of swine, bird and human influenza.
Bars and nightclubs, schools, gallery openings and sporting events were canceled until further notice. The government issued a decree giving the Health Ministry power to enter people’s homes, close public events, isolate patients and inspect travelers and their baggage.
Calderon stressed that the flu was curable and that Mexico had sufficient supplies of antiviral medicine to deal with the situation. The Mexico deaths are of particular concern because the victims have tended to be young, healthy adults, whereas garden-variety flu mostly kills infants and the elderly.
In New York, about 200 of the 2,700 students attending St. Francis Preparatory High School in Queens had missed school last week because of flu-like symptoms, prompting school officials to notify the health department.
A preliminary analysis of viral samples obtained from nose and throat swabs from nine affected students found that eight tested positive for influenza A. Because none matched the known H1 and H3 sub-types of human flu, they were considered “probable” cases of swine flu, said New York City Department of Health and Mental Hygiene Commissioner Thomas Frieden.
The St. Francis students had just returned from spring break, during which time some might have traveled to Mexico, Frieden said.
Kansas health officials said Saturday that they had confirmed swine flu in a married couple living near Abilene, Kan., after the husband visited Mexico. The couple, who live in Dickinson County, were not hospitalized, and the state described their illnesses as mild.
The previously confirmed cases in the Southwestern United States — seven in California and two in Texas — also have been relatively mild. Only one patient has been hospitalized, and none has died.
Numbers
7% Fatality rate in Mexico among those infected with the current flu strain
2.5% Fatality rate of those infected during the Spanish flu pandemic of 1918-19
1% Fatality rate among those infected with seasonal flu
Recent pandemics
1918: The Spanish flu was possibly the deadliest outbreak of all time. It was first identified in the U.S. but became known as the Spanish flu because it received more media attention in Spain than in other countries, which were censoring the media during World War I. The 1918 flu was an H1N1 strain and struck mostly healthy young adults. Killed about 40 million to 50 million people worldwide.
1957: Known as the Asian flu, it was sparked by an H2N2 strain and was first identified in China. There were two waves of illness during this pandemic; the first wave mostly hit children, while the second mostly affected the elderly. It caused about 2 million deaths globally.
1968: Known as the Hong Kong flu, it was the mildest of the three. It was first spotted in Hong Kong and spread globally over the next two years. The people most susceptible to the virus were the elderly. About 1 million people were killed by this H3N2 flu strain.
The Associated Press
Swine-flu facts
Q. What is swine flu?
A. Swine flu is a highly contagious acute respiratory disease normally found in pigs. It spreads through tiny particles in the air or by direct contact. According to the World Health Organization, it tends to infect large numbers of a given pig population, killing between 1 percent and 4 percent of those affected. Not every animal infected displays symptoms.
Q. Where do outbreaks occur?
A. Swine flu is considered endemic in the United States, and outbreaks in pigs have been reported elsewhere in North America, South America, Europe, Africa and parts of East Asia.
Q. How high is the risk of a pandemic?
A. The risk of a pandemic has increased. Health officials worry the swine flu might develop into a form easily spread among humans. To do this, it could combine with a human flu virus or mutate on its own into a transmissible form. Experts worry that the more the virus circulates, the more likely a pandemic strain will emerge. But there is no way to predict when a pandemic strain will develop.
Q. Does a vaccine exist?
A. Pigs in North America are routinely vaccinated for swine flu, but no vaccine exists for humans. In any case, the flu virus evolves quickly, meaning that vaccines are soon obsolete. Health officials say there is no suggestion that the vaccine prepared for seasonal flu will protect against swine flu.
Q. What other treatment is there?
A. The swine-flu virus detected in Mexico and the United States appears to respond to treatment with oseltamivir (Tamiflu) and zanamivir (Relenza). In terms of prevention, maintaining good hygiene, for example regular hand-washing and staying a safe distance from those infected, might help.
