Another method of creating a candidate virus also mixes wild virus with a second, fast-growing strain, but instead of growing them in eggs, lets the viruses mingle in a special solution while scientists manipulate them through a complex technique called reverse genetics.

CNN: Candidate virus for H1N1 vaccine arrives at CDC

Some doctors paint a scary worst-case scenario: A flu pandemic breaks out and beats down the immune systems of millions of people, and then staphylococci--the hospital strain and the nastier variant in the community--run wild on a killing spree.

FORBES: Germ Warfare

Of the 50 patients and 33 wild armadillos the researchers analyzed from the U.S., 25 patients and 28 armadillos shared a genetically identical strain of leprosy bacteria.

CNN: Armadillos linked to leprosy in humans