WASHINGTON - Federal officials warned on Tuesday that swine-flu related deaths were likely in the United States as the disease that killed scores in Mexico continued to spread across the world and governments intensified steps to battle the outbreak.
The number of confirmed cases in the United States was raised to 64, but states and cities were reporting more suspected cases. In New York, the city's health commissioner said "many hundreds" of schoolchildren were ill at a school where some students had confirmed cases.
President Barack Obama asked Congress for $1.5 billion in emergency funds to fight the fast-spreading disease.
Cuba banned flights to Mexico, where public life is being altered dramatically by illness.
So far, no deaths linked to the disease have been reported outside Mexico.
But Richard Besser, acting director of the Centers for Disease Control and Prevention, said in Atlanta: "I fully expect we will see deaths from this infection.
That was echoed by U.S. Homeland Security Secretary Janet Napolitano. "It is very likely that we will see more serious presentations of illness and some deaths as we go through this flu cycle," she said.
Napolitano added that in a normal seasonal influenza season, about 35,000 deaths are linked to the flu.
Besser said the U.S. has 64 confirmed cases across five states, with 45 in New York, one in Ohio, two in Kansas, six in Texas and 10 in California.
New York has the largest number of swine flu cases, with a heavy concentration at a Catholic school in Queens section of New York City, where students recently went on a spring break trip to Mexico.
There also were indications that the outbreak may have spread beyond the school, with two people hospitalized and officials closing a school for autistic kids down the street. Those two hospitalizations are in addition to the five hospitalizations announced by the CDC, including three in California and two in Texas.
"It is here and it is spreading," New York City Health Commissioner Thomas Frieden said. "We do not know whether it will continue to spread."
Meanwhile, swine flu was ruled out as the cause of one of two recent deaths being investigated by the Los Angeles County coroner's office. Coroner's Assistant Chief Ed Winter said Tuesday that lab testing is still pending in the case of the second fatality, but that swine flu is not now suspected.
Cuba banned flights to Mexico, where swine flu is believed to have killed more than 150 people. Mexico City, one of the world's largest cities, cracked down even further on public life, closing gyms, swimming pools and pool halls and ordering restaurants to limit service to takeout. Earlier, the city shut down schools, state-run theaters and other public places.
But for all the government intervention, health officials around the world suggested the flu virus strain was spreading so fast that efforts to contain it might prove ineffective.
"Border controls do not work. Travel restrictions do not work," World Health Organization spokesman Gregory Hartl said in Geneva, recalling the SARS epidemic earlier in the decade that killed 774 people, mostly in Asia, and slowed the global economy.
Obama's request for $1.5 billion in emergency funds would help build drug stockpiles and monitor future cases as well as help international efforts. White House spokesman Robert Gibbs said the flu outbreak requires "prudent planning" and not panic.
Cuba was the first country to impose an outright travel ban. But the United States and a number of other countries, including Canada, Israel, France and the European Union's disease control agency have warned against nonessential travel to Mexico.
The swine flu already has spread to at least six countries besides Mexico, prompting WHO to raise its alert level on Monday but not call for travel bans or border closings.
Around the world, officials hoped the outbreak would not turn into a full-fledged pandemic, an epidemic that spreads across a wide geographical area.
"It's a very serious possibility, but it is still too early to say that this is inevitable," the WHO's flu chief, Dr. Keiji Fukuda, told a telephone news conference.
Flu deaths are nothing new in the United States or elsewhere. The CDC estimates that about 36,000 people died of flu-related causes each year, on average, during the 1990s in the United States.
But the new flu strain is a combination of pig, bird and human viruses for which humans may have no natural immunity.
New Zealand reported that 11 people who recently returned from Mexico had contracted the virus. Tests conducted at a WHO laboratory in Australia confirmed three cases of swine flu among 11 members of the group who were showing symptoms, New Zealand Health Minister Tony Ryall said.
Israel's Health Ministry confirmed two swine flu cases in men who recently returned from Mexico. One has recovered and the other was not believed to be in serious danger, health officials said.
Meanwhile, a second case was confirmed Tuesday in Spain, Health Minister Trinidad Jimenez said, a day after the country reported its first case. The 23-year-old student, one of 26 patients under observation, was not in serious condition, Jimenez said.
With the virus spreading, the U.S. stepped up checks of people entering the country and warned Americans to avoid nonessential travel to Mexico.
"We anticipate that there will be confirmed cases in more states as we go through the coming days," Homeland Security Secretary Janet Napolitano said on NBC's "Today" show on Tuesday.
On Capitol Hill, a Senate panel held an emergency meeting on the disease.
"Based on the pattern of illness we're seeing, we don't think this virus can be contained. ... But we do think we can reduce the impact of its spread, and reduce its impact on health," Rear. Adm. Anne Schuchat, the CDC interim science and public health deputy director, told a Senate Appropriations health subcommittee.
"There's a lot of anxiety right now across the country," subcommittee Chairman Tom Harkin, D-Iowa, said.
"It's important for people to know there's a lot that we can do," Schuchat told Harkin. "The investments that have been made in preparedness are making a difference."
Still, she warned, not only might the disease get worse, "it might get much worse."
"We don't have all the answers today," she added.