Fleas Fleas are found throughout the world and cause misery to humans and animals because of their irritating bites and ability to transmit disease. The species most commonly in the home is the cat flea, Ctenocephalides felis . Contrary to what the name implies, cat fleas infest both cats and dogs equally. They can carry or transmit various diseases such as the bacterium that causes bubonic plague.
Fleas often cause serious allergies to infested animals and humans.
Fleas are attracted to some people more than others. Others are allergic to the flea saliva and experience distress even though they are not getting bitten any more often than anyone else. Particularly sensitive people suffer intense itching for up to a week and sometimes come down with a generalized rash. Dryness is fatal to larvae because they cannot close their breathing holes to retain moisture. Thus, hot, dry summers reduce flea populations and rainy summers produce larger populations.