Flu cases increase, but US officials optimistic

But health officials in the United States expressed some optimism about the course of the disease. And the Mexican health minister said that in his country, the hardest hit and where the flu was first reported, the worst had passed.

Janet Napolitano, US homeland security secretary, yesterday that WHO might "very well" elevate its flu alert from Level 5 to Level 6, the highest, this week. WHO officials have also indicated that such a move may be imminent.

Napolitano emphasized, however, that even the highest-level WHO warning was not in itself a cause for grave concern. It would indicate that the flu strain has reached pandemic status, but there can be a pandemic of a mild disease, and this strain is looking milder than first thought.

"Level 6, which they very well could go to this week, all that means is that it is widespread around the world," Napolitano said on CBS's "Face the Nation."

Other American health officials spoke of "encouraging signs" in the flu's course, even while cautioning of the substantial uncertainties surrounding any new strain.

The WHO said Saturday that there was still no evidence of the flu's sustained spread outside North America, a requisite condition for raising its alert level.

Still, 19 countries have now been affected, including Colombia, which yesterday reported the first confirmed case of swine flu in South America.

The course of the disease in Mexico - where 19 confirmed deaths have been linked to the flu, with many other deaths suspected - is now "in its phase of descent," Jose Angel Cordova, health minister, told a news conference, Reuters reported. Scientists suspect many of the dead in Mexico might have waited too long - a week on average - to seek help.

Worldwide, more than 900 people have been infected, predominantly in North America. Spain now has 44 confirmed cases, more than any other European country, but all the patients had responded well to treatment, the health ministry said. Britain, Italy, and Germany reported new cases, the Associated Press reported.

In Spain, all but four of the cases involved a patient who had recently traveled to Mexico, the Spanish Health Ministry said. Spain is a hub for travel to Mexico, with dozens of flights each day between the two countries.

The ministry said it would seek to tighten controls at airports today but did not offer any details about additional measures. Passengers arriving from affected areas this week have been completing questionnaires about possible virus symptoms, and cabin crews have been supplied with gloves and masks in an effort to isolate suspected cases and contain contagion.

In the United States, officials said that 244 people had confirmed cases of the flu in a total of 30 states, but they expected the virus to spread throughout the country.

Still, Napolitano and other top officials emphasized that since its deadly initial spread in Mexico, the disease had generally shown a milder face.

Dr. Richard Besser, acting head of the Centers for Disease Control, pointed to "encouraging signs" that the strain might end up being no worse than a normal seasonal flu. In New York City, for example, the disease had spread quickly through a private high school in Queens, but the cases were "not that severe, and that's encouraging," he said on "Fox News Sunday."

Kathleen Sebelius, who last week was confirmed as secretary of health and human services, told Fox that there was cautious optimism in part because "the lethality which initially presented itself as part of the Mexican situation - deaths of an age group you don't typically see" - was not being seen elsewhere.

In Mexico, nine of the 19 dead were between the ages of 21 and 39, which is unusually high.

But experts were careful to balance their cautious optimism with warnings that the flu might yet get worse.

"These viruses mutate, these viruses change, these viruses can further reassort with other genetic material, with other viruses," said Dr. Michael Ryan, WHO's global alert and response director. "So it would be imprudent at this point to take too much reassurance."

Infectious disease experts said it will be important to watch what this virus does in coming weeks and months, particularly in the Southern hemisphere, which will soon confront its winter flu season. If the flu takes hold there, that will be a red flag to scientists.

"This virus could dampen here during the summer per usual, and go to the Southern Hemisphere and pick up steam there and come back to bite us in our winter season next January and February, and it might come back in a more virulent form," said Dr. William Schaffner, a public health and infectious disease expert at Vanderbilt University.