Global health authorities warned Wednesday that swine flu is threatening to bloom into a pandemic.
Even as the outbreak appeared to stabilize at its epicenter in Mexico, the virus spread farther in Europe. A toddler who succumbed in Texas became the first death outside Mexico.
The outbreak seemed to be leveling off in Mexico, where 168 people have died. Eight deaths were confirmed as swine flu, and the rest suspected. But the World Health Organization said the global threat is nevertheless serious enough to ramp up efforts to produce a vaccine against the virus.
"It really is all of humanity that is under threat during a pandemic," WHO director-general Margaret Chan said in Geneva. Chan emphasized the need for calm, but at times spoke as if a pandemic had already begun.
The Geneva-based agency raised the pandemic threat alert level for the second time in three days, from phase 4 to phase 5, just one notch below a full-scale pandemic, after concluding that the virus was causing sustained outbreaks in the United States and Mexico.
The heightened alert is intended to prompt every nation to activate an emergency response plan, pharmaceutical companies to increase production of antiviral drugs and help speed development of a vaccine, and bankers to help poor countries afford measures to fight the virus, officials said.
"Containment is no longer a feasible option," said Dr. Keiji Fukuda of the WHO. "The world should focus on mitigation. We recommend not closing borders or restricting travel."
The pronouncement came as officials in Maryland said they were investigating six probable cases of the disease and at least 10 more were under investigation at the University of Delaware.
The first death from the disease in the United States involved a 23-month old boy from Mexico City who died Monday at Texas Children's Hospital in Houston. The child, who had unspecified "underlying health problems," according to U.S. health officials, flew with his parents from Mexico City to Matamoras, Mexico, on April 4 to visit family in nearby Brownsville, Texas.
Texas Gov. Rick Perry issued a disaster declaration. High school sports events were suspended across Texas until May 11 and 130,000 students were sent home for at least two weeks.
President Barack Obama offered his "thoughts and prayers and deepest condolences" to the toddler's family and to other victims and their loved ones. He urged local authorities to report all suspected cases and close schools where infections are reported.
One day after being confirmed as Health and Human Services Secretary, Kathleen Sebelius stressed the government was "determined to fight this outbreak and do everything we can to protect the American people." However, she added: "We expect to see more illness, more hospitalizations and unfortunately, we're likely to see additional deaths."
Public health authorities have been worried the virus would start producing the kind of severe pneumonia and deaths that so far had been limited to Mexico, where the epidemic began. "The clinical picture in the United States is looking a bit more like the Mexican situation," said Nancy Cox, a flu expert at the Centers for Disease Control and Prevention.
The number of known cases in the U.S. hit at least 93, with infections confirmed in at least six new states: Maine, Massachusetts, Michigan, Arizona, Indiana and Nevada, more than doubling the number of states with confirmed cases. A Marine stationed in California also has a suspected case.
Asked whether the new phase would change the U.S. approach, Homeland Security Secretary Janet Napolitano said, "We have been preparing all along as if this is going to be a stage 6. Our efforts have been to stay ahead of whatever number the WHO assigns."