Sunday, May 21, 2006
The Variability of Influenza
The lead-off article of Answers In-Depth is Genetic Variance of Influenza Type A Avian Virus and its Evolutionary Implications.
This paper highlights the known variability of influenza. [note to readers -- as highlighted many times in this blog, Creationists agree with change, but change within bounds and according to type, not arbitrary change] The paper notes several interesting characteristics of influenza type a:
- Made of 8 RNA molecules
- Affects the widest range of organisms of the classes of influenza, but is native to birds.
- The variance of the genes that code for surface proteins are the ones most essential in immunity
- When two strains of Influenza Type A infest the same organism, they can swap genetic material
- Because of the massive amount of reproduction of influenza, it has more of an ability to undergo "hit-and-miss" types of mutational events
The author notes that among the strains of avian flu that were not previously applicable to humans, only twelve cases have been reported in humans since 1997, and none of them further infected humans after the first interaction.
Influenza is continually changing its genome, but even with the large amounts of change that it undergoes, it is still entirely change within type. It was unclear to me from the article whether or not the types of changes it can undergo would allow switching from birds to human, nor what specifically the characteristics of influenza that are not transmissable from human to human.
"An Indonesian who died of bird flu after nursing his sick son may have caught the virus in a case of direct human-to-human transmission, the World Health Organization said on Tuesday.
WHO gave its first details of the case of a family cluster of H5N1 avian influenza infections in which six people have now died, and said it was still looking for the source of the outbreak. If it was a case of human-to-human transmission, the virus has not spread very far, it emphasized.
It would not be the first case of human-to-human transmission. WHO believes some limited human-to-human transmission has occurred before in other countries, but as in the Indonesian case, it did not last for long."