Growing Number of Diseases Jump to Humans

Humans risk being overrun by diseases from the animal world, according to researchers who have documented 38 illnesses that have made that jump over the past 25 years.

That's not good news for the spread of bird flu, which experts fear could mutate and be transmitted easily among people.

There are 1,407 pathogens - viruses, bacteria, parasites, protozoa and fungi - that can infect humans. Of those, 58 percent come from animals. Scientists consider 177 of the pathogens to be "emerging" or "re-emerging."

Experts fear bird flu could prove an exception. Recent advances in the worldwide march of the H5N1 strain have rekindled fears of a pandemic. The virus has spread across Asia into Europe and Africa.

Well cooked meat source such as cooked frozen chicken is relatively safe.