Saying that 100,000 Americans are likely infected with a new flu virus, U.S. health officials on Friday announced they were easing the warning on travel to Mexico.
Texas health officials also reported on Friday that a man from Corpus Christi died from the new strain of H1N1 swine flu, raising the number of U.S. deaths to five.
The U.S. Centers for Disease Control and Prevention estimated that at least 100,000 Americans were infected with the virus, which has been behaving much like seasonal flu. The CDC has reported 4,714 confirmed and likely cases of the new H1N1 swine flu virus.
The CDC's Dr. Martin Cetron said the agency would lower its warning on travel to Mexico to a travel advisory, mostly for people who are at high risk of complication from influenza.
"CDC would likely be posting a downgrade to the travel warning that is currently up regarding Mexico, which is at a level four alert that suggests folks defer nonessential travel to Mexico. That will be downgraded to a travel precaution," Cetron told reporters in a telephone briefing.
"A very high proportion of our hospitalizations are occurring among those who have underlying health conditions that put them at risk for complications, and our travel precaution will be particularly providing advice to those individuals regarding seeing their physician and getting specific advice on the feasibility and reasonableness for them," Cetron said.
The virus is behaving much like a seasonal influenza strain — spreading rapidly and causing mainly mild disease, but severe illness in some people.
Looking at pattern
The CDC cautioned that not every suspected case is being tested now, as it is more useful to look at the pattern of disease as opposed to counting the numbers. The World Health Organization reports more than 7,500 cases globally, most in the United States and Mexico.
"Somewhere between 7 percent to 10 percent of the U.S. population each year gets influenza, which is maybe 21 million to 30 million people a year," the CDC's Dr. Dan Jernigan told the briefing.
"If we had to make an estimate, I would say that the amount of activity we're seeing with our influenza-like illness network is probably upwards of maybe 100,000," Jernigan said, adding that he would need more data to confirm that.
Jernigan said he could not confirm reports that another new strain of H1N1 — a group of flu viruses that includes not only the new strain but circulating seasonal influenza strains — had been discovered in Mexico.
"We've heard of some reports about that, but I have not had any direct information about the specifics of that case. So there's ongoing dialogue between us and the folks that are in Mexico and so as we know more about that, we will be able to let people know," Jernigan said.
Earlier on Friday, the World Health Organization warned against a false sense of security from waning and apparently mild outbreaks of H1N1 flu, saying the worst may not be over.
WHO Director-General Margaret Chan said there remained "great uncertainty" about the new strain that continues to spread and could pose particular threats in Southeast Asia.
But she could not say whether or when the U.N. agency might raise its pandemic alert to the highest level from the current 5 on a scale of 6. The trigger would be if sustained spread was confirmed in communities outside of North America.