Travelers coming from Cancun, Mexico, wear masks against the H1N1 flu virus as they arrive in Duesseldorf, Germany, April 30.

Washington — Outbreaks of the novel strain of H1N1 influenza continue worldwide, infecting at least 331 people in 11 countries, with suspected cases in the thousands. In Mexico, schools, theaters, restaurants and other nonessential services are closed for five days beginning May 1.

On April 29, the World Health Organization (WHO) raised the worldwide pandemic alert level to phase 5, a strong signal that a pandemic is imminent and a notice to countries that it is time to organize, communicate and implement planned mitigation measures.

In an April 30 briefing, Dr. Keiji Fukuda, WHO assistant director-general for health security and environment, said there were no immediate plans to move to phase 6, which indicates that a global pandemic is under way.

Mexico so far has reported 97 laboratory-confirmed cases with seven deaths, the United States has confirmed 109 cases with one death, and the following countries have confirmed cases but no deaths: Austria (one case), Canada (19), Germany (three), Israel (two), Netherlands (one), New Zealand (three), Spain (13), Switzerland (one) and the United Kingdom (eight).

On April 29, the United States announced it would provide $5 million to WHO and the Pan American Health Organization to support Mexico’s efforts to contain the spread of H1N1. The funds will provide equipment and supplies to help with disease diagnosis and medical treatment for those suffering from the infection.

“The government of Mexico in concert with authorities around the world is taking strong action to contain the spread of H1N1 influenza and assess the dangers it may pose,” Chargé d’Affaires Leslie Bassett at the U.S. Embassy in Mexico City said in a statement. “The United States, as a neighbor and friend, is collaborating with Mexico and the international community to address this global concern.”

Through the Centers for Disease Control and Prevention (CDC) and the U.S. Agency for International Development (USAID), the United States is working closely on the ground and around the world with Mexican health authorities and international organizations.

HELP FROM H5N1

Despite the growing number of H1N1 infections and uncertainties surrounding the outbreak, health officials are crediting the global response to another potential pandemic flu — highly pathogenic H5N1 avian influenza — with preparing countries to meet the current challenge.

“The world is better prepared for an influenza pandemic than at any time in history,” WHO Director-General Dr. Margaret Chan said in an April 29 briefing. “Preparedness measures undertaken because of the threat from H5N1 avian influenza were an investment and we are now benefiting from this investment. For the first time in history, we can track the evolution of a pandemic in real time.”

Bishop Kearny High School in New York City is closed April 30 as a precaution against the spread of the new H1N1 flu.

In 1996, scientists isolated highly pathogenic H5N1 avian flu virus from a farmed goose in Guangdong province, China. The next year, in 1997, H5N1 outbreaks occurred in poultry at farms and live-animal markets in Hong Kong and — the first known human infections — in 18 people, six of whom died.

Six years later, in 2003, outbreaks among poultry occurred in South Korea and Thailand and the virus began to spread. Today, as of April 23, H5N1 has killed or prompted the destruction of hundreds of millions of domesticated and wild birds in more than 60 countries, infected 421 people in 15 countries and killed 257 of them.

PANDEMIC PREPAREDNESS

The international focus on avian flu generated action worldwide. Nearly all governments put in place basic planning for pandemic flu activities. National surveillance systems with supporting laboratory and field investigation services were reinforced. Networks of laboratories, surveillance systems and response mechanisms enhanced regional capacity to detect and respond to pandemic flu and other diseases.

In that effort, the United States provided $949 million to support international actions in more than 100 nations targeting preparedness and communication, surveillance and detection, and response and containment.

“If you look at what we have been practicing for the past five years and what we’ve been planning for, pandemic flu was number one,” CDC Acting Director Dr. Richard Besser said at an April 30 briefing.

“While microbes don’t read the [pandemic mitigation] plan and you need to move away from the plan pretty soon after day one,” he added, “the fact that we’ve been exercising several times a year for a pandemic and state and local health departments have been getting tremendous resources for this has meant that when it arrived, we didn’t have to sit down first and say, ‘Let’s talk about flu.’ With a lot of emerging infections that’s where the conversation is starting.”

Besser said CDC scientists have isolated the H1N1 strain and are growing supplies of it for distribution to vaccine manufacturers if experts decide that a vaccine should be produced against the novel virus.

Discussions are ongoing, he added, but “we would complete the production of next year’s seasonal flu vaccine … and then manufacturers would switch over to manufacturing vaccines for this H1N1 disease.”

Besser said if the decision is made to produce an H1N1 vaccine, some doses might be ready by September or October.

More information about H1N1 is available on special pages at the Web sites of the CDC and WHO.