No, no case reported. Fleas transmit some diseases to humans, such as the bubonic plague, which can be found in CO, UT, NM, and AZ. Rabies virus is in the saliva of infected animals. However, near the time of death, a rabid animal could have rabies virus in other parts of its body. Hypothetically, a flea could bite the animal just at the "right time", and then bite a human soon afterwards, and maybe transmit the virus.