Snippet of my consult from some years back...
A flea jumped out from the fur of a kitty cat I was examining.
As I parted the kitty's fur along the neck. I saw another 5 to 6 fleas scrambling frantically around, trying to hide from the light.
The owner's son screamed in terror when he looked over my shoulder.
But the owner told the son to "keep quiet" because "it is natural for the cats to have fleas."
I was dumbfounded.
Fleas are NOT naturally found on the cats.
There is no commensalism or symbioses between the fleas and ANYONE.
Fleas bite everyone.
They are not our friends.
Also, your cats can get tapeworms (Dipylidium caninum) from fleas.
Some Tapeworms (Echinococcus species), found in cats may cause serious disease in humans if the eggs are ingested. Rare reports of Dipylidium caninum infections in children have been recorded, though these infections are not associated with significant diseases.
But why would you want to take the risks?
Can we be absolutely sure that fur, debris etc don't enter our mouth or our children's mouth when we/they play with and kiss your cats?
Just get rid of the fleas. Please.