Quote:
Originally Posted by mynah
It depends on how you define "species jump". Some would say a species jump had taken place once a disease had been transmitted from the host species to another species for the first time: In this article, for instance rabies due to Australian bat lyssavirus is listed among diseases that had undergone a species jump, even though only two human cases (both transmitted through bat bites) have been recorded. One should also keep in mind the stringent measures some countries took to limit the spread of avian flu: Vietnam, for instance, culled its entire farmed bird population and started anew with imported hatchlings. |
Fair enough. Some would say such things. I dont consider the avian flu a true jump yet, as it is not spreading as canine distemper did through the seal populations (and apparently the lion populations of Africa), nor is it like the parvo virus jump from cats to dogs in the late 70s or early 80s. A true jump (imo) requires the disease to be transmittable on a comparable level with the original host infection rate. The avian bird flu H5N1 tears through bird populations with a high percentage of them becoming ill and then dying. This also makes the efforts of Vietnam importing new populations of chickens pretty pointless, in that wild birds are the main carriers of H5N1. Unless of course they are importing birds who are carrying some type of immunity to this strain, as some wild asian mallards seem to have.
As far as rabies (and I am not sure its a good example), well theres all kinds of strains out there which have become specialized for one type of host (canine rabies) but is transmittable to a whole host of animals, man included. Is it really a new jump or an old genetic code that rears its head during mutations, hence the bat transmission being something that should be expected, rather than declared a new specie jump? Does anyone know where these particular bats obtained their original infection from? Would be kinda ironic if it was from some domestic animal, say a dog brought over on one of the prison transports to australia so many years ago.
Quote:
Originally Posted by mynah
The WHO defined three stages and six phases in the development of a flu pandemic: By their definition, avian flu had reached stage two (pandemic warning period) and was entering phase 4 ("Minor outbreaks of limited distribution from human to human occur, although such outbreaks are highly localised. This appears to indicate a viral strain that is not yet well equipped to infect humans.") when the tide was turned.
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What tide was turned? Theres like 65,000 flu related deaths in the USA a year and not one of them related to H5N1. We have what? Less than 400 H5N1 (or is it 800?) deaths worldwide with the potential for a handful of them being person to person transmissions. Does the potential exist for H5N1 making a transition into something like the spanish flu? Sure. But it also has the potential of making that 'true jump' without being more than a typical flu season with all its new strains and variations of the same old, same old.
If I remember right, they have already seen mutation in the ebola virus which allows more of its hosts to survive. Its really not in a virus best interest to kill its host, well not kill them fast anyways. I suppose this is part of the evolutionary reason why viri and bacteria can mutate so fast. Whoops, I didnt mean to burn down the house Honest!
