In fiction and popular culture, parasitic characters appear as a metaphor for the threat and spread of disease. But they've also played for laughs.
People caught and died from plague long before it caused major epidemics like the Black Death in the middle ages. Could what scientists call cultural resistance be what kept the disease under control?
By finding out more about the cat flea, researchers could maybe identify better pest control measures.
Tungiasis, a disease caused by fleas, is neglected and needs action in sub-Saharan Africa.
Everywhere humans go, we take our pets. Fleas are along for the ride, spreading everything from typhus to bubonic plague.
You can get out from behind the sofa, reports of an invasion of mutant insects are exaggerated.
Fleas have lived with people for as long as people have lived with pets.