To:               virology@net.bio.net
From:             bhjelle@unm.edu
Subject:          Re:  Re: Ebola virus outbreak in Africa
Date sent:        17 May 1995 17:36:31 -0600

In article <3pbkkq$odn@hydra.cc.umb.edu>,
>>
>
>     BL ratings do not reflect how dangerous a disease causing organism is
>to humans, but how careful people in the labs think they should be with the
>organisms. If it scares the crap outta them, its BL4. If not, it's not.
>
>     I think that Ebola could be safely handled with P3 containment or
>even carefully followed P2 conditions. BL4 isn't perfect, just read about
>hole in glove incidents. 
>
The BL ratings are more than how "scary" viruses are, or their
crude mortality rates. They are based upon their infectiousness
and route of infection (aerosol is worse than percutaneous),
their case-fatality, availability of vaccine, and past experience
with laboratory infections and consequences thereof.
Thus HIV is BL2-BL3 but Machupo is BL4, even though HIV has
a higher mortality. 


Brian