Saturday, December 17, 2005

Bird-flu mortality and Intelligent Design

A piece aired on National Public Radio yesterday discussed what appeared to be an alarming mortality rate in humans due to the H5N1 virus (bird flu): 50 percent. Certainly sounds scary should there be a pandemic among humans, with human-to-human transmission, should that occur. This figure, however, is very much higher than scientists expect would be the case should a pandemic develop. For one thing, the 50-percent mortality rate reported is for cases where the persons were known to be infected by bird-to-human transmission of H5N1, and likely does not include a significant number of cases that escaped identification (in part because of mild or lacking symptoms). Anthony Fauci, director of the Nation Institute of Allergy and Infectious Diseases, went on to explain that viruses that evolve to permit human-to-human transmission become less virulent (they wouldn't be able to spread very well if they killed all of the victims before infecting others)--this is a characteristic of evolution. This was seen in the case of the infamous pandemic of 1918, in which the mortality rate was nearer 1.5 to 2 percent.

So here's another example of the utility of evolutionary theory. Based on what we know about how evolution works, we can make predictions (H5N1 may very well evolve the capacity for human-to-human transmission; and, if it does, it will very likely evolve decreased virulence. What predictions can the assertion of Intelligent Design Creationism make about this virus and its effect on humans?


4 Comments:

Anonymous Anonymous said...

Note: I am not a supporter of Intelligent Design, however I admit that there is an ID explanation for this particular type of question.

Simpy put: The human body's immune system is adaptable by design.

9:25 AM  
Blogger Mark said...

This is not a question of the human body's ability to combat the virus--it's a matter of the virulence of the virus itself. Of course, the ID crowd can always claim that's how the Designer wanted the redesigned virus to work (which is why ID is not science--basically, the same explanation is used for any situation).

7:12 PM  
Anonymous Lori said...

Actually, those of us who have been tracking the progress of H5N1 know that a reduction in mortality and/or virulence is not necessary for a pandemic to spread rapidly. There are other considerations, such as: ability to infect a variety of mammalian hosts; long incubation period during which host is contagious; asymptomatic migratory birds; ability of the virus to live on inert surfaces for as much as 72 hours; not to mention the ability for humans, animals & virus to travel around the world in a matter of hours.

Furthermore this virus is dispelling the commonly held scientific belief that random mutation, genetic shift & drift, etc. take a long time. Recombination is much more efficient. IMHO (in my honest opinion), H5N1 supports the creationist point of view.

12:37 AM  
Blogger Mark said...

Certainly there are complexities in the spread and virulence of a virus; the factors lori mentions have been or can be studied by the science of biology. Thus far, we apparently have not seen human-to-human transmission of H5N1, but we predict that this type of transmission may evolve in the virus. Recombination (as well as horizontal gene transfer and other processes) are mechanisms of evolution along with mutation and the others. There is nothing here to support a creationist view. Indeed, what is the creationist view in this regard? Traditionally, creationists have argued that critters were created in the form in which they are presently known. When confronted with undeniable changes over time, they have shifted to admitting variations within "kind" or microevolutionary changes. I contend that viruses can change significantly, through evolutionary mechanisms (see also arguments at Aetiology http://scienceblogs.com/aetiology/2006/01/luskin_still_doesnt_get_it.php#comments) and that there simply is no creationist explanation other than "that's how God made it" which at once explains everything and therefore explains nothing.

7:34 AM  

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