Tracking the next pandemic: Avian Flu Talk |
"I am ’Freakin Out’, WHO chief Nabarro |
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Posted: January 28 2006 at 1:13pm |
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24 Jan 2006 | 23:38
(This was the only story that reported references to Nabarro freakin' out.) Kuwait News Agency (KUNA) Nabarro: "I worry every day about human-to-human transmission". Asked by the Kuwait News Agency (KUNA) whether he is freaking out from that possibility, Nabarro said in a news briefing in Geneva that he worries every morning as he starts his day with reviewing his e-mails from this development unfolding. Nabarro said (David Nabarro, the U.N. coordinator on avian and human influenza/Senior System Coordinator ) that "we are all standing on a deep edge and not knowing how far we are going to fall" when it happens. This is why, he added, everybody is focused on getting ready, because if preparation is not done before the crisis, then it is too late. He stressed that those who say the moment the pandemic starts its too late to get prepared, and noted that those people are absolutely right. "Not only I am 'freaking out', to use the correspondents expression, and not mine, not only is that worry or anxiety because of the impact of a possible pandemic, but there is also that worry and anxiety because so many people when I talk to them about getting prepared seem to imply that we have months ahead to get prepared," he said. However he added that "I say to them it might not be months, it could be that we get human to human transmission tomorrow, so please act as though it is going to start tomorrow, don't keep putting off the difficult issues". "I am scared of the possible arrival of human influenza pandemic, everybody is scared of it," he said. http://www.kuna.net.kw/Home/Story.aspx Edited by Rick |
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FYI and a bit of an explanation for those who may be new here. http://www3.niaid.nih.gov/news/focuson/flu/research/primer/d efault.htm Focus on the Flu Research: Flu Primer
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Influenza A virus. Credit: CDC |
Influenza viruses are classified as type A, B, or C based upon their protein composition. Type A viruses are found in many kinds of animals, including ducks, chickens, pigs, whales, and also in humans. The type B virus widely circulates in humans. Type C has been found in humans, pigs, and dogs and causes mild respiratory infections, but does not spark epidemics.
Type A influenza is the most frightening of the three. It is believed responsible for the global outbreaks of 1918, 1957 and 1968. Type A viruses are subdivided into groups based on two surface proteins, HA and NA. Scientists have characterized 16 HA subtypes and 9 NA subtypes.
Type A subtypes are classified by a naming system that includes the place the strain was first found, a lab identification number, the year of discovery, and, in parentheses, the type of HA and NA it possesses, for example, A/Hong Kong/156/97 (H5N1). If the virus infects non-humans, the host species is included before the geographical site, as in A/Chicken/Hong Kong/G9/97 (H9N2). There are no type B or C subtypes.
In nature, the flu virus is found in wild aquatic birds such as ducks and shore birds. It has persisted in these birds for millions of years and does not typically harm them. But the frequently mutating flu viruses can readily jump the species barrier from wild birds to domesticated ducks and then to chickens. From there, the next stop in the infectious chain is often pigs.
Pigs can be infected by both bird (avian) influenza and the form of influenza that infects humans. In a setting such as a farm where chickens, humans and pigs live in close proximity, pigs act as an influenza virus mixing bowl. If a pig is infected with avian and human flu simultaneously, the two types of virus may exchange genes. Such a "reassorted" flu virus can sometimes spread from pigs to people.
Depending on the precise assortment of bird-type flu proteins that make it into the human population, the flu may be more or less severe.
In 1997, for the first time, scientists found that bird influenza skipped the pig step and infected humans directly. Alarmed health officials feared a worldwide epidemic (a pandemic). But, fortunately, the virus could not pass between people and thus did not spark an epidemic. Scientists speculate that chickens may now also have the receptor used by human-type viruses.
Influenza virus is one of the most changeable of viruses. These genetic changes may be small and continuous or large and abrupt.
Small, continuous changes happen in type A and type B influenza as the virus makes copies of itself. The process is called antigenic drift. The drifting is frequent enough to make the new strain of virus often unrecognizable to the human immune system. For this reason, a new flu vaccine must be produced each year to combat that year's prevalent strains.
Type A influenza also undergoes infrequent and sudden changes, called antigenic shift. Antigenic shift occurs when two different flu strains infect the same cell and exchange genetic material. The novel assortment of HA or NA proteins in a shifted virus creates a new influenza A subtype. Because people have little or no immunity to such a new subtype, their appearance tends to coincide with very severe flu epidemics or pandemics.
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