WHO Chief: Swine Flu Could Return 'With a Vengeance'

The head of the World Health Organization says the swine flu influenza A-H1N1 epidemic could return "with a vengeance" despite the Mexican government's insistence the disease has reached its peak and is declining.

Margaret Chan told the Financial Times Monday the decline in mortality rates outside and within Mexico does not mean the outbreak is coming to an end. She said she hopes the virus "fizzles out" [fades away]. Chan said if the virus continues to spread, "it would be the biggest of all outbreaks the world has faced in the twenty-first century."

Last week, WHO raised the alert level to five, indicating that a level six global pandemic could be imminent. Chan said in the newspaper interview she is not predicting a pandemic, but she is preparing for it. The World Health Organization has sent 2.4 million anti-viral treatments to 72 developing countries for a use in a possible pandemic.

Mexico's Health Minister Jose Angel Cordova said Sunday the outbreak appeared to have peaked in Mexico between April 23 and April 28, and that the number of severe cases is declining. Mexico is the center of the international outbreak.  It has reported 19 deaths and another 487 infections.  The neighboring United States has confirmed 226 cases nationwide and one death.

Scientists have yet to determine the strength and lethality of the previously unknown flu strain, which is a mix of swine, avian and human viruses. The new strain has raised concerns because it is spreading outside the normal flu season, and has been deadly among young healthy adults. Health experts are concerned the H1N1 flu could become a more serious threat during the s winter flu season, when typical influenza viruses cause widespread respiratory illness.

At least 20 countries have confirmed cases. The first case in South America was confirmed Sunday in Colombia. El Salvador also reported its first two cases.

Some information for this report was provided by AFP, AP and Reuters.