Roaches

Cockroaches spread 33 kinds of bacteria, including: E Coli, salmonella, six parasitic worms and seven other types of human pathogens. 

The parasitic worms that cockroaches spread are tapeworm, roundworm, hookworm, pinworm, whipworm, and other variations.

Other problems are diarrhea, cholera, dysentery and typhoid fever.