WASHINGTON — A leading U.S. health expert said this morning that while "there are encouraging signs" of a leveling off in the severity of the swine flu threat, it's still too early to declare the problem under control.

"I'm not ready to say that yet," Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention, said when asked about indications by Mexican health authorities that the disease has peaked there.

Besser did tell network television interviewers that "what we're seeing is an illness that looks very much like seasonal flu. But we're not seeing the type of severe disease that we were worrying about."

He noted that roughly 36,000 people die each year in this country from the winter flu, so it's still a serious matter.

At least 247 cases of swine flu virus have been confirmed in 30 states so far, and Besser said that "we are by no means out of the woods."

"In previous pandemics," he said, "there have been waves and you don't know what this virus is going to do."

U.S. confirmed cases from the CDC or the states: New York, 63; Texas, 43; California, 29; Arizona, 18; South Carolina, 15; Delaware, 10; Louisiana, New Jersey and Massachusetts, seven; Colorado, four; Florida, Indiana, Illinois, Nebraska, Ohio, Oregon, Virginia and Wisconsin, three; Connecticut, Kansas and Michigan, two; and one each in Alabama, Iowa, Kentucky, Minnesota, Missouri, Nevada, New Hampshire, New Mexico, North Carolina, Pennsylvania, Rhode Island, Tennessee, Idaho and Utah.

There has been one death in the United States, a 23-month-old toddler who died after he was brought to this country from Mexico.