Jay and Nancy Mone wrote in message <199906192159.SM00181@[188.8.131.52]>...
>In order for a virus to be efficiently spread by a blood-sucking insect,
>a couple of things must be true:
>(1) The virus must be in high titer in the plasma for a substantial
>period of time.
>(2) The virus must use the arthropod host as an incubator, rather than
>simply as a vehicle.
>>HBV and HCV certainly do achieve high-titered, prolonged viremia, but
>once inside an arthropd vector, they don't survive. This is probably due
>to the fact that the virus can't infect the insect's cells.
>>During most of the infectious cycle of HIV, high-titered viremia is not
>seen, and again, the virus is unable to survive in the arthropod.
>>Concerning Graham Shepherd's response, virtually everyone says that these
>viruses are not spread by any insects. If they were, there would be no
>risk groups, since we would all be equally at risk of getting bitten.
It's pretty difficult to prove an absolute negative - I just wanted to
prompt a little thinking about the question itself. I know in practice
you're right, but under the right conditions it might happen. (They would be
pretty artificial conditions.) Now, does the same argument apply to vampire