Winnipeg, CDC Lab Find Swine Flu Viruses

Winnipeg, CDC lab find swine flu viruses

By Helen Branswell,
THE CANADIAN PRESS
24th April 2009

Mexican authorities confirmed Friday they have found human infections with swine flu virus, a discovery that suggests the outbreak there may be linked to person-to-person spread of swine flu in the southwestern United States.

Canada’s National Microbiology laboratory found at least 16 positive cases of swine flu out of a shipment of 51 clinical specimens sent from Mexico to Winnipeg for testing, sources say. Those specimens included lung biopsies and nasal swabs, among other types of specimens.

Mexican officials said the U.S. Centers for Disease Control also found positives among samples tested in the CDC labs in Atlanta.

The World Health Organization expressed serious concern, saying it is considering whether it needs to raise the global pandemic alert level and has put the experts who would advise WHO on whether to go that route on alert to be ready to meet. The WHO activated its emergency operations centre on Friday.

The WHO is also deliberating whether it should launch an effort to try to contain the spread of a virus that appears to have possible pandemic potential. Modelling studies have suggested it might be possible to snuff out an emerging pandemic virus and the WHO has made plans over the years to try containment.

“We can’t say for sure that either a phase change or a rapid containment operation will happen. But both have been considered and are being considered,” spokesman Gregory Hartl said from Geneva.

“I still don’t think we have enough information to be able to say that this is a pandemic or not. Because there are questions over transmissibility, let’s say, of the virus. And we need to know more about how easily transmitted the virus is.”

Hartl said there have been no reports of infections in any other countries.

The unusual influenza A H1N1 swine viruses were first reported earlier this week, when the CDC announced it had found two human cases of infection with this never-before-seen virus. Testing shows the virus is vulnerable to Tamiflu and Relenza, the two main drugs used to fight flu.

There has been no public confirmation that the Mexican virus is identical to the U.S. viruses.

Though human H1N1 viruses have been circulating for decades, it is not clear how much protection previous infection with them would confer against a virus made up predominantly of swine flu genes. The virus also has some bird genes and one human gene.

U.S. authorities have confirmed seven cases of swine flu infection in people in Southern California and Texas over the past few days. The seven range in age from nine to 54 years of age. All have recovered from the infection; one needed hospitalization.

But the news coming out of Mexico paints a different story.

In a television interview, Secretary of Health Jose Angel Cordova Villalobos said there have been 45 deaths, but only 16 of those were directly related to the flu in question.

An estimated 943 people are ill, the television report said.

The majority of the cases are occurring in young, previously healthy adults in their mid 20s to mid 40s, reports suggest. Experts aren’t certain if all of those people are sick with this virus or if other flu or respiratory viruses are also circulating and muddling the picture.

Schools were closed Friday in Mexico City, one of three areas of the country where cases have been reported.

Hartl said the WHO is sending staff to Mexico to help authorities there get a better handle on the scope of the problem.

“We’re extremely concerned because we’re looking at five different influenza events which may or may not be connected,” he said, referring to California, Texas and three possibly linked outbreaks in Mexico.

“But they are unusual events, either because of the time of the year that they happened and or because of the people that have been affected. This is a great concern to us and we have activated our strategic health operation centre which is a 24-hour around-the-clock command and control centre.”

Canada and the United States have also launched their emergency control centres, signalling this is an event they want to track around the clock.

The world is currently at level 3 of the WHO’s six-rung pandemic alert ladder, because of ongoing sporadic cases of human infection with the H5N1 avian flu virus. Phase 3 means there are occasional human cases with a novel flu virus.

WHO would need the advice of an expert panel to move up to Phase 4 or beyond. Phase 6 is a pandemic.