Fleas on cats is always a challenge because cats are so much more sensitive to toxins than dogs. Getting rid of fleas on kittens is even more difficult. At 3 weeks old, they are too young for most types of flea powder, spray or even flea baths. Treating the mother is a marginal option because the kittens will be climbing over her and nursing from her. Unfortunately ignoring the fleas till the kittens are older is also a poor choice.
Arrange the three bowls on a table or other stable surface where they are not like to be spilt. Pour the flea spray solution into one bowl, have the next bowl full of a cleaning solution that will not create fumes when combined with the flea spray, and finally a clean bowl of water. Seat yourself nearby with a roll of paper towels, a flea comb and the cat or kittens that need treated.
Place a sheet or pillow case on your lap. Wait till the mother cat has fed the kittens and has left the nest for food and water. Comb her thoroughly with a fine tooth flea comb. When the comb becomes clogged with fleas, dunk the whole thing in the flea spray liquid. Do not use the comb on the cat till you have cleaned it in the sudsy water, then in the clean water. Dry it off with a paper towel, making sure no flea liquid or soap remains on it. Feed her or confine her to keep her away from the kittens after treatment.
Pick up an untreated kitten. Gently comb the fleas off the baby. Be sure to get the tummy, behind the ears and at the base of the tail, as these are places fleas like to hide. When the little one is as free of fleas as you can manage, put it with its mother or in a clean box. Repeat the process till all the kittens have been groomed.
Repeat this cleaning process daily till the fleas are gone or until the kittens are 6 weeks old. At that time, ask your veterinarian to recommend a safe substance to use on mother and babies to make sure the fleas are really gone. If you have a serious infestation that does not yield to combing and cleaning, you may need to talk with him sooner.
Clean the kittens environment thoroughly each day throughout the process. Wash bedding, vacuum out or replace their nest box daily. Vacuum and clean the rest of your house, making sure to get cracks and corners. The combing process will get rid of the adult fleas. By washing the bedding, vacuuming and changing their box, and cleaning your home, you are getting rid of the flea eggs.
Make the flea combing social time. If you are gentle, and take pains to make the grooming feel good for the cats, they will respond in a positive fashion. Dispose of vacuum cleaner bags out-of-doors immediately after vacuuming for fleas.
This process is not 100 per cent effective. In the event of an extreme infestation, consult your veterinarian.