Obviously, mosquitos carry West Nile. I believe there is some evidence of mosquitos carrying Lyme, although everyone thinks it's just ticks. However, why wouldn't other blood-sucking insects by able to carry the Lyme bacteria if they bite an infected animal or person? As one Lyme book I'm reading states, do mosquitos, biting flies, and fleas have special Lyme filters that allows them not to carry Lyme? Probably not.