Scientists investigating the 1918-1919 "Spanish Flu" pandemic believe that that strain of H1N1 influenza caused so much damage partly by causing victim's immune system to go into overdrive.
Researchers exhumed bodies that were buried in permafrost in Alaska and Canada, and managed to isolate the virus. When primates were infected with this strain, the scientists observed massive spikes in cytokines.
Cytokines are produced by cells when they become infected by a virus. They act as a signal to the body's immune system which then sends antibodies to that area.
The problems caused by the Spanish Flu virus were because it was such a new and unusual strain. The victims cells produced cytokines at a much higher rate, and affected organs were flooded by antibodies. Influenza is a respiratory illness and infected patients lungs were flooded with so many antibodies that their lungs were overwhelmed, ultimately leading to pneumonia.
The current outbreak seems to be affecting healthy young adults most severely, so it seems that it may be harming people via a similar mechanism.
The danger is as the virus resides in more hosts there is a much greater risk of the virus exchanging genetic material with other strains of influenza. Could this make the virus even more exotic to the immune system, and make "cytokine storms" more severe?
Showing posts with label bird flu. Show all posts
Showing posts with label bird flu. Show all posts
Tuesday, 28 April 2009
Sunday, 26 April 2009
Are We About To See The Next Flu Pandemic?
On Tuesday, April 21, the US Center for Disease Control (CDC) issued an alert that there had been two cases of swine flu in humans in California. On April 23 the Mexican government confirmed that the recent spate of flu like illnesses in Mexico were connected to this strain of swine flu.
Today cases of swine flu have been reported in Canada, with more suspected in New Zealand, Spain, France, UK, Israel, Columbia and Brazil. So far the virus may have killed 86 people, all in Mexico - although it is difficult to confirm the precise strain in each case. At the moment the picture isn't entirely clear, but it seems that this new and virulent strain of flu is spreading across the globe.
It should be made clear that this is by no means a pandemic at the moment; but does it have the potential to develop into one? From Wikipedia, these are the 3 conditions that the WHO says are needed for a pandemic to develop:
Although there have been outbreaks of swine flu before, this one is a novel strain, containing genetic material from swine flu from North America, Europe and Asia, along with elements of bird flu and common human flu. This is a result of different strains of the flu virus co-existing in the same host, where they swap genetic material. This is a new disease.
- Emergence of a disease new to a population.
- Agents infect humans, causing serious illness.
- Agents spread easily and sustainably among humans.
The strain can clearly infect humans, and be passed from human to human. Non of the victims from outside Mexico seem to have had any contact with infected pigs, although all at this stage have recently returned from Mexico. The relatively high mortality rate in Mexico makes this a serious illness. Even if all the suspected cases were confirmed (many may be more common flu, or flu like illnesses) the mortality rate would be about 6%, compared with the the Spanish Flu outbreak of 1918 - 1919 which is believed to have had a mortality rate of 2.5% - 5%.
The strain does seem to be able to spread easily amongst humans, the scale of infection in Mexico suggests this. The question is can it spread sustainably? There are still only a handful of cases outside Mexico, and if these can be contained and controlled then a global pandemic may be averted, although the apparent scale of the infection in Mexico would still present a high risk.
So the outbreak certainly isn't a pandemic yet, and hopefully it won't become one, but the risk is there, and the WHO, CDC and governments and health care agencies around the world will be working very hard to fight this.
For now the advice is simple: maintain high levels of personal hygiene - wash your hands more frequently and more thoroughly, and if you fell ill with flu like symptoms stay at home - don't go to work, university, school, etc. but stay at home and seek medical help if your condition worsens.
You can keep up to date by following these on twitter:
@BreakingNews
@mpoppel - covering various news conferences etc. for BreakingNews.
@CDCemergency
@healthmap
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