Fleas!

[fd3]

F'in infested by the blighters.  Not clear why as mog1 never leaves the house and both mogs have been treated.
We use the drops on back of neck, but now considering putting the cats in the bath.

[Jaded]

As well as the back of the neck, comb with a flea comb and have a glass of water with a couple of drops of washing up liquid in it. After each successful comb, put the fur and fleas into the water, the fleas sink to the bottom.

Also, once the cats are treated, wash their bedding. Get a treatment for the carpets and soft furnishings, as the flea eggs survive for ages there.

The back of the neck stuff should be used over several months. Oh, and some treatments are lessening in effectiveness. So vet supplied ones are more effective than shop bought ones.

[Flite]

I think fleas have become resistant to most over-the-counter treatments.
We use a spot-on treatment prescribed by our vet (Nexgard Combo, but there are others).
You do need to use it every 4 weeks, but it protects against internal (eg tapeworms) as well as external parasites.
Initially, you will need to clear the house of fleas and eggs.
Vacuum getting into all the nooks and crannies, wash, spray, repeat. Vet will advise on best spray to use.
Make sure their beds can be washed at a high temperature.
But once done, if you maintain the treatment on the cats, you shouldn't get re-infested or need to treat the house.

Our cat is a hunter and picks up masses of fleas from rabbits. The treatment means they will not stay on her for long, but I do sometimes use a flea comb and forceps to pick them off her ears just to make her more comfortable/stop scratching.

[mrcharly-YHT]

Spraying soft furnishings is a good idea.

Quite frequently the fleas start hatching and getting active when central heating comes on.

Indorex is good. You can spray it on bedding and it is pet safe.

[fd3]

Using bombs as a spray alternative and doin' good hoovering.
Word on the street is split on the neck drops from the vets - lots of "it's the same thing but more expensive"

We will be shampooing and flea combing the cats tomorrow, when the comb and shampoo arrive.  They are in different quarentines until then.