HIV-1 Adaptation to host/various musings

Ian A. York york at
Fri Oct 20 08:28:14 EST 1995

In article <4682iq$cv9 at>, A.J.Cann <nna at> wrote:
>Have to comment on this. The key phrases here are "adapt to their hosts" & 
>"mortality rate of well over 99.99999%" (do you mean 100% - not true; 
>99.9% would be more accurate). Snag is that humans are not the natural 

I mean neither 99.9% nor 100%.  Last time I checked on this, I think I 
found 5 examples of people surviving rabies following onset of clinical 
signs.  Since I also found (last easy-to-find number was 1985) that at 
least 20,000 people per year die of rabies, I think my 99.99999% is 
pretty accurate - certainly more accurate than 99.9%.  Moreover, I think 
I recall seeing in ProMed that the 5th known survivor is now suspected to 
have been infected by a related lyssavirus, rather than rabies itself.  
Do you have a reference for your 99.9%?

>host of rabies virus - they are dead end hosts who do not play a 
>significant part in the transmission of the virus over "thousands of 
>years". Hence each human infection is essentially a new event & the virus 
>does not have chance to "adapt to it's host" in evolutionary terms.

Can you name *any* species which survivies rabies infection?  The 
prevalent belief that bats can have persistent infection (again this is 
as of the last time I checked) seems to be wrong; they simply don't die 
quite as fast as other species.


Ian York   (york at
Dana-Farber Cancer Institute, 44 Binney St., Boston MA 02115
Phone (617)-632-3921     Fax  (617)-632-2627

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