The World Health Organization (WHO) raised its alert level late on Tuesday from three to five – three steps short of declaring a full pandemic.
EU health ministers are to meet on Thursday to discuss the outbreak, which health officials suspect has killed about 150 people in Mexico.
After cases were confirmed in Canada, on April 2009 – all involving only mild illness – the government said it was stepping up surveillance for possible new cases and urged people to take precautions like frequent hand-washing.
The number of Canadians confirmed to have suffered mild cases of the human form of swine flu swelled to 19, with new cases reported in Alberta, Ontario and British Columbia.
The new cases in Ontario, Alberta and British Columbia were anticipated, and do not change the federal government’s course of action, Canada’s chief public health officer, Dr. David Butler-Jones, the greater odds that some will be severe, told a teleconference on Tuesday.
Ontario’s acting chief medical officer of health, Dr. David Williams, said four people in the country’s largest province were confirmed as having the same strain of influenza since mid-April.
Ref: http://news.bbc.co.uk/2/hi/americas/8021547.stm
How Swine Flu Outbreak Emerged
Flu viruses mutate over time causing small changes to proteins on their surface called antigens. If the immune system has met a particular strain of the virus before, it is likely to have some immunity; but if the antigens are new to the immune system, it will be weakened.
The influenza A virus can mutate in two different ways; antigenic drift, in which existing antigens are subtly altered, and antigenic shift, in which two or more strains combine. Antigenic drift causes slight flu mutations year on year, from which humans have partial, but not complete, immunity. By contrast, the new strain of H1N1 appears to have originated via antigenic shift in Mexican pigs
The name “swine flu” is a slight misnomer as it is believed pigs acted as a mixing pot for several flu strains, containing genetic material from pigs, birds and humans. Most humans have never been exposed to some of the antigens involved in the new strain of flu, giving it the potential to cause a pandemic.
The new virus has made the jump from pigs to humans and has demonstrated it can also pass from human to human. This is why it is demanding so much attention from health authorities. The virus passes from human to human like other types of flu, either through coughing, sneezing, or by touching infected surfaces, although little is known about how the virus acts on humans.
What is swine flu?
Swine flu is a respiratory disease, caused by influenza type A which infects pigs.
There are many types, and the infection is constantly changing. Until now it has not normally infected humans, but the latest form clearly does, and can be spread from person to person – probably through coughing and sneezing.
What is new about this type of swine flu?
The World Health Organization has confirmed that at least some of the human cases are a never-before-seen version of the H1N1 strain of influenza type A. H1N1 is the same strain which causes seasonal outbreaks of flu in humans on a regular basis.
But this latest version of H1N1 is different: it contains genetic material that is typically found in strains of the virus that affect humans, birds and swine.
Flu viruses have the ability to swap genetic components with each other, and it seems likely that the new version of H1N1 resulted from a mixing of different versions of the virus, which may usually affect different species, in the same animal host. Pigs provide an excellent ‘melting pot’ for these viruses to mix and match with each other.
How dangerous is it?
Symptoms of swine flu in humans appear to be similar to those produced by standard, seasonal flu. These include fever, cough, sore throat, body aches, chills and fatigue.
It is worth remembering that seasonal flu often poses a serious threat to public health: each year it kills 250,000 – 500,000 around the world.
So far, most cases of swine flu around the world appear to be mild, albeit with diarrhoea more common than it is with seasonal flu.
How worried should people be?
When any new strain of flu emerges that acquires the ability to pass from person to person, it is monitored very closely in case it has the potential to spark a global epidemic, or pandemic.
——————————————————————————————————————————
Can the virus be contained?
The virus appears already to have started to spread around the world, and most experts believe that, in the era of readily available air travel, containment will be extremely difficult.
The World Health Organization says that restricting flights will have little effect. It argues that screening of passengers is also unlikely to have much impact, as symptoms may not be apparent in many infected people.
Can it be treated?
The US authorities say that two drugs commonly used to treat flu, Tamiflu and Relenza, seem to be effective at treating cases that have occurred there so far. However, the drugs must be administered at an early stage to be effective.
Use of these drugs may also make it less likely that infected people will pass the virus on to others.
The UK Government already has a stockpile of Tamiflu, ordered as a precaution against a pandemic.
It is unclear how effective currently available flu vaccines would be at offering protection against the new strain, as it is genetically distinct from other flu strains.
A new bespoke vaccine is being worked on by scientists in the UK and the USA, but it may take months to perfect it, and manufacture enough supplies to meet what could be huge demand.
A vaccine was used to protect humans from a version of swine flu in the US in 1976.
However, it caused serious side effects, including an estimated 500 cases of Guillain-Barré syndrome. There were more deaths from the vaccine than the outbreak.
________________________________________
What About the A1H1N1 Vaccines?
Chances are you’ve heard of thimerosal. A preservative once widely used in baby shots, it can still be found in some flu vaccines. Thimerosal contains small amounts of mercury. At high levels, mercury causes nerve and brain damage.
But the form of mercury that bio-accumulates, or builds up in body tissues, is methyl mercury. Thimerosal contains ethyl mercury, a form that the body eliminates.
Thimerosal in vaccines got a bad name in the 1990′s after a now discredited report linked certain baby shots with autism. But at the height of the thimerosal controversy, in 1999, pediatricians asked the pharmaceutical industry to take the chemical out of baby shots. It did. Since then, numerous studies have shown that children exposed to the amount of thimerosal in baby shots don’t suffer any more neurological problems than do children who have not been exposed. (Autism rates did not decline as a result.)
Public health officials figured you might be.
Much of the A1H1N1 vaccine becoming available this fall won’t have thimerosal, says some University influenza-vaccine experts. It is being used only in flu vaccine packaged in multi-dose units. It won’t be in single-dose units or in the nasal-spray flu vaccine.
That said, multi-use vials are often used by busy flu clinics (using sterile techniques and one-use-only needles). So if you’re concerned, ask before getting the shot.
—————————————————————
