In article ,
veteran wrote:

I have heard that bacteria can travel 10 feet when the toilet is
flushed. didn't i hear of a study that proved that? like another
reason to put the lid down.

snip

bwahahahaha:

http://www.straightdope.com/classics/a990416.html

"In 1975 Professor Gerba published a scientific article describing the
little-known phenomenon of bacterial and viral aerosols due to toilet
flushing. The more you learn about it, the scarier it sounds. According
to Gerba, close-up photos of the germy ejecta look like "Baghdad at
night during a U.S. air attack." The article ominously depicts a "floor
plan of experimental bathroom with location of gauze pads for viral
fallout experiments." A lot of virus fell on those gauze pads, Gerba
found, and a lot of bacteria too. In fact, significant quantities of
microbes floated around the bathroom for at least two hours after each
flush.

"As Professor Gerba's research would later determine, however, the
bathroom was hardly the most dangerous part of the house, microbe-wise.
The real pesthole: the kitchen sponge or dishcloth, where fecal
coliform bacteria from raw meat and such could fester in a damp,
nurturing (for a germ) environment. Next came the kitchen sink, the
bathroom sink, and the kitchen faucet handle. The toilet seat was the
least contaminated of 15 household locales studied. "If an alien came
from space and studied the bacterial counts," the professor says, "he
probably would conclude he should wash his hands in your toilet and
crap in your sink.""