Expert: Dana Krempels, Ph.D. - 12/9/2007

Question
If someone carrying a virus(for example, Anthrax) died, and a carnivore were to
eat the body, could the virus become a danger again?

Answer
Dear Alec,

Whether a virus can "jump species" and become a dangerous pathogen in the new host depends on the virus and on many other conditions.  Most pathogenic viruses are fairly host-specific, and will not cause problems in the situation you describe in your question.  However, some viruses *can* infect a new host and become a real plague.

I personally know a veterinarian who was studying in Australia, where Viral Hemorrhagic Disease was released to control the feral rabbit population.  She reported that there have been confirmed cases of dead predatory birds that may have scavenged dead rabbit carcasses or caught live rabbits.  She told me that the bird tissues tested positive for the VHD virus, but that the Australian authorities are keeping the situation very hushed up for fear of a panic outbreak.  I can't confirm her story, but she is a very reliable, critical vet and I have no reason to think she would concoct a story like this.

Viruses such as HIV and Ebola didn't just magically appear to infect humans.  They were no doubt residing harmlessly in a host species which had evolved resistance to them.  One hypothesis is that both viruses may have jumped to humans when human predators ate infected animals, though there are other ways the viruses could have crossed over to humans.

So the answer to your question is:  Yes.  But not always.  It depends on the virus, the species in question, and probably on other factors that are not fully understood.

There is an excellent article in the December 3, 2007 issue of the New Yorker about retroviruses crossing species and even affecting our evolutionary history.  I would *strongly* recommend it if you are interested in this sort of thing.  It is fascinating!

Hope this helps!

Dana