I have heard not, but my son had a cold and then one of our cats got a
cold...  My cats are indoor only cats, so it makes me wonder.
-Jen

Highly improbable.

Human proteins are quite different from cat proteins and this makes it
unlikely that a human virus can infect a cat and vice versa. This is why
owners can continue to care for FIV (Feline Immunodeficiency Virus), for
example, and not worry about contracting some sort of hybrid FIV-AIDS
syndrome.

Cross-species viral infections *do* occur, but they are rare. There is
some evidence that the H5N1 (bird flu) virus can cross at least two
species barriers, those being cat and human. West Nile Virus also
evidences the ability to infect different species. This is why both
viruses are newsworthy, and the press can create the misconception that
cross-species infection is commonplace.

Cross-species bacterial infections are more commonplace than cross-
species viral infections, but they are still relatively rare.

If you get a chance, leaf through a Microbiology or Virology textbook
sometime. There's some fascinating stuff in there, but then I'm a bit
biased since that's my major.

Regards,

Thanks to those who responded. I've heard that colds can't cross
species, but my cat, like Jen's, is indoor only. I can't imagine how
else, other than from me, he caught the cold. In the future, I'll be
more careful when I have a cold, just in case...