The World Health Organization convened an emergency meeting of experts in Geneva on Saturday to advise on whether to escalate the global pandemic alert in response to outbreaks of swine flu in people in Mexico and the southwestern United States.
WHO Director General Dr. Margaret Chan said the group would counsel her on whether the worrying disease outbreak, which is reported to have claimed at least 20 lives so far, should be deemed a public health emergency of international concern.
It is also expected to recommend on whether the global pandemic alert level should be raised from the current Phase 3 to Phase 4 or higher. Phase 6 means a pandemic has been declared.
The group advises but the decision rests with Chan. It was not clear if the WHO director general would make a decision Saturday.
“The situation is evolving quickly,” Chan said from Geneva during a media teleconference.
“A new disease is, by definition, poorly understood. We do not yet have a complete picture of the epidemiology, or the risk, including possible spread beyond the currently affected areas.”
“Nonetheless, in the assessment of WHO, this is a serious situation which must be watched very closely.”
Mexican authorities have confirmed 20 deaths, believe more than 40 more may be linked to the outbreak and have reported more than 1,000 suspect cases in three areas of Mexico.
The United States has reported eight cases, all of relatively mild disease, in and around San Diego, Calif., and in San Antonio, Texas.
Canadian authorities said Friday there have been no confirmed cases in Canada to date.
In fact, Chan said the WHO currently has no reports of cases of swine flu in countries other than Mexico and the United States, but she urged nations to be on the lookout for spikes in pneumonia or influenza-like illness, especially if they appear in places where flu season should be over.
The unusual swine flu virus was first detected in California about 10 days ago. But investigations of infections in the U.S. and reports from Mexico suggest cases have been occurring for several weeks if not more than a month.
“This is an animal strain of the H1N1 virus and it has pandemic potential because it is infecting people,” Chan said.
“However, we cannot say based on the currently available laboratory, epidemiological and clinical evidence whether or not it will indeed cause a pandemic.”
Chan said the viruses causing infections in Mexico and parts of the southwestern United States are “genetically the same.” The virus is a never-before-seen hybrid containing genes from swine viruses from the Americas and Asia as well as some genes from avian and human flu viruses.
Scientists at Canada’s National Microbiology Laboratory and the U.S. Centers for Disease Control have typed and sequenced virus samples from Mexico over the past several days.
“This is an interesting virus. It’s a brand new virus, not only to humans but to the world,” Dr. Frank Plummer, scientific director of Canada’s national lab, said at an Ottawa news conference on Friday.
“About 80 per cent of the virus is highly related to a North American body of swine flu that’s been around for a number of years, but about 20 per cent of it comes from an Eurasian variety of swine flu first seen in Thailand, so it’s recombined to create something totally new.”
“How it did that, where it did it, when it did it, I don’t think we know yet.”
Testing has shown the viruses are resistant to two old flu drugs, amantadine and rimantadine, but are susceptible to the flu antivirals, Tamiflu and Relenza, which are in many national emergency stockpiles, including Canada’s.
Chan said Mexico has “a sizable supply” of Tamiflu.
The WHO director general said while Mexican authorities have been co-operative, the picture there remains too blurred to make a judgment on how widespread infections are or about what percentage of cases are severely ill or dying. The WHO has sent experts to Mexico to help with the assessment and the CDC is also sending a team of experts.
“We are seeing a range of severity from mild to severe to some deaths,” she said.
“It is important that we get to the bottom of the matter as soon as possible. Speed is important. Capacity is important. And we are addressing both.”
A number of reports have suggested previously healthy young adults — people ranging from their mid 20s to mid 40s — are making up a higher than expected percentage of the cases. With regular flu, young children and the elderly are generally at highest risk.