By MIKE STOBBE
Atlanta: Why has the swine flu engulfing Mexico been deadly there, but not in the United States? Nearly all those who died in Mexico were between 20 and 40 years old,
and they died of severe pneumonia from a flulike illness believed caused by a unique swine flu virus. The 11 U.S. victims cover a wider age range, as young as 9 to over 50.
All those people either recovered or are recovering; at least two were hospitalized.
“So far we have been quite fortunate,” said Dr. Anne Schuchat of the U.S. Centers for Disease Control and Prevention on Saturday, just hours before three new U.S. cases were confirmed.
Health experts worry about a flu that kills healthy young adults, a hallmark of the worst global flu epidemics. Deaths from most ordinary flu outbreaks occur among the very young and very old.
Why the two countries are experiencing the illness differently is puzzling public health experts, who say they frankly just dont know. It may be that the bug only seems more deadly in Mexico. And while experts believe Mexico is the epicenter of the outbreak, they are not certain if new cases are occurring or if the situation is getting worse. They also dont know if another virus might be circulating in Mexico that could be compounding the problem.
A big question is: Just how deadly is the virus in Mexico?
The seasonal flu tends to kill just a fraction of 1 percent of those infected. In Mexico, about 70 deaths out of roughly 1,000 cases represents a fatality rate of about 7 percent. The Spanish flu pandemic of 1918-19, which killed an estimated 50 million worldwide, had a fatality rate of about 2.5 percent.
The Mexican rate sounds terrifying. But its possible that far more than 1,000 people have been infected with the virus and that many had few if any symptoms, said Dr. Michael Osterholm, a prominent pandemic expert at the University of Minnesota. U.S. health officials echoed
him. In Mexico, they were looking for severe diseases and they found some.
“They may not have been looking as widely for the milder cases,” said Schuchat of the CDC. “The U.S. health agency sent two investigators to Mexico on Saturday to
help,” she said.