[Diddle E. Squat]

The tapeworm eggs are spread by a human host who doesn't practice good hygiene after using the restroom.

Lots of fools on this thread were bragging about how they don't wash their hands:

Survey finds airport restroom users seldom wash

[Old Professer]

The thing I found most interesting about your 31/2 year old link was that the most fastidious hand washers were in Toronto during and following the SARS scare where a total of 32 Torontons were said to have died from SARS while the murder rate plodded along at 94 for the year.