Life Cycle and Control of Cat Fleas

Flea is the common general name for wingless insects of the order Siphonaptera with mouthparts adapted for piercing skin and sucking blood. Fleas are external parasites, living by ingesting the blood of birds and mammals including bats and humans. Fleas exist worldwide and upwards of 2,200 species have been identified.

The Cat flea is: Ctenocephalides felis

The cat flea's primary host is the domestic cat, but this is also the primary flea infesting dogs in most of the world. The cat flea can also maintain its life cycle on other carnivores and on the Virginia opossum.

Humans can be bitten but cannot be infested, so a population of cat fleas cannot be sustained by humans usually. An experiment showed that a flea had to feed continually on human blood for 12 cosecutive hours to produce eggs that could hatch. Not likely but possible.

What does a flea look like

Adult fleas are wingless and have flattened sides. Colour ranges from reddish brown to black. Fleas have many backward pointing bristles which help as the fleas move in his hosts fur. Large back legs make the flea a great jumper.

Life Cycle of the Flea

Although the female flea lays her eggs on the host, the eggs dry and slip out of the fur and fall onto the cat's bed or resting area. The flea eggs hatch after an incubation period of up to 21 days. Flea larvae will not hatch on the cat

The eggs hatch into larvae which hide from light. This means they will burrow into a carpet or deep in the cat's bed. During this stage the flea larvae eat organic matter and in particular feed on flea dirt, the adult flea fecal matter that falls out of the cat's coat.

The flea larvae metamorphoses in 3 stages. They then spin a cocoon, that sticks to surrounding dirt and is camouflaged, and pupate. The young flea usually needs the warmth, availability of food, vibrations, carbon dioxide and humidity of a potential host to trigger emergence from the pupal stage. The cat flea has been extensively studied. The pupal stage can be as short as 4 days. In unfavourable conditions, the flea can stay in its cocoon for several months.

Within 48 hours of emerging the young flea starts feeding.

The cat flea is not a fussy eater and will nibble on dogs racoons, weasels, dogs, skunks, rabbits, squirrels, foxes, calves, and of humans as well as many other animals.

A female flea can produce about 20 eggs a day and lives 4-6 weeks.

Where does a cat get fleas?

Fleas are picked up from bedding and resting spots where cats normally lay.

There are more fleas during the summer than during the winter. Higher summer temperatures and humidity are better for flea growth. Preferred conditions are 27C-32C with 75-92% relative humidity.

Can a cat fight fleas

An actively grooming cat can reduce the adult flea population it carries by 50%. Go Kitty!

Younger cats are more likely to have larger flea loads than older cats. Its not clear if the older can has a acquired resistance OR if their grooming habits are better.

Older or weak and sick animals are not so good at grooming and can have more fleas.

The down side of grooming and eating lots of fleas is that if the fleas are infected with tapeworms then the cats gets infected with tapeworm.

Effect on Host

A few fleas are not particularly harmful. However its not very comfortable to be itchy and a small flea population can grow quickly. Fleas should be controlled.

Fleas can attack humans and can carry some nasty bugs

Sometimes fleas cause allergic reactions on the host cat. This is called flea allergy dermatitis. See Allergies in Cats page These cats will have scabby bumps on their skin.

Large infestations, particularly on small animals can cause dehydration or severe anemia.

Over grooming and scratching can result in scabs, hair loss and skin irritation and infections.

Fleas can transmit some diseases and parasites

Tapeworm

Dipylidium caninum, is a tapeworm that infects organisms afflicted with fleas, including dogs, cats, and humans, especially children.

Eggs are passed in the host's feces and ingested by fleas. The flea then needs to be ingested by another mammal after the tapeworm larvae partially develop. Ctenocephalides felis, the cat flea can spread this tapeworm if they have access to the fecal matter. In order to be infected a human has to ingest an infected flea.

Pulicosis

This is a skin condition caused by flea bites including Ctenocephalides felis, the cat flea. Symptoms include skin irritation, swelling. In some people the reaction can cause ulcers of the mouth, soreness and restlessness. More rarely condition can spread to the lymph system and nervous system and become quite serious.

Cat scratch fever

(Bartonella) can be transmitted by fleas.

Fleas including cat fleas have been linked to the transfer of many diseases

How do I know if my cat has fleas?

• Persistant scratching.
• Check the belly of the cat, it is usually possible to find fleas fleeing the scene! Look around the base of the legs.
• Flea Dirt is a sure sign. Put your cat on a white paper, or a newspaper with lots of white and ruffle up his coat including his belly. If you see black specs falling on the paper this is likely flea dirt. Wetting the dirt will turn it red and show it is blood. If when wet it is not red and bloody, then its just regular dirt.
• Combing, It is also possible to comb out fleas with fine tooth comb if your cat's fur is not too thick and your cat lets you, Its not a good way to control but you might catch a flea.
• Sometimes the fur at the base of the tail is thin and in poor condition.
• Scabby skin. Fleas is the most common allergy in cats.

Flea Control

To be successful flea control has to be done on 2 fronts. The cat and his bed and sleeping spots

Treating the cat will get rid of the fleas and treating the bedding will get rid of the eggs larvae and eggs.

There is more need for flea control in the warmer months. Because of the ability of the flea to slow down its development in poor conditions, a flea infestation can persist for several months with no animal present.

University of Kentuky has a good article on flea control. It is not specific to cats so before you use some of the suggested flea control insecticides CHECK THAT THEY ARE SAFE FOR CATS.

Different insecticides are licenced in different geographic areas. Check with your vet, or with the the ministry of Agriculture or with Public Health departments for what is recommended in your area.

Treating the Cat

• Keep the cat out of areas that are hard to reach and clean so that he doesn't get re-infested. Flea eggs fall off the cat and can stay alive for several months before hatching.
• Bathing in Vet approved flea and tick shampoos is effective to remove adult fleas.
• Flea collars are also available but carry some risks and are not very effective.
• Powders and sprays are available. They have to be applied carefully in order that the cat does not inhale dangerous powder or aerosols. Or for that matter that YOU do not inhale nasty flea killer.
• Fumigating Flea bombs are dangerous and should not be used.
• Drops can be applied on the shoulder blades and some are safe and effective while others are dangerous.
• There are many different products that target various stages of development of the flea.
• Do not use Dog products on Cats. Some dog flea treatment products containing permethrin can cause deaths in cats. Even just being close to dogs that have been treated with it can be dangerous to cats.

Flea Shampoo

This works but fleas will run to any dry spots on the head and ears. Your cat will probably object to a bath if she's not used to it.

Flea Powders

Flea powder work as long as its on a cat, but it doesn't stay on the cat very well. The cat will groom and will swallow some of the powder. It can also be inhaled and be irritating.

Collars

Flea collars are impregnated with active ingredients that kills fleas or inhibit flea growth. They work around the neck but are not great the further you get from the collar. There are also problems associated with the safety of a collar on a cat. Irritation and hair loss can happen where the collar touches the cat. Some flea collars are quite toxic. There are safer and more effective ways of controlling fleas on your cat.

Spot Drops

Spot treatment usually gets applied on the neck or shoulder blades. There are different products available. Do not use Dog products on Cats Many are poisonous to cats in particular permethrin.

I have used Bayers Advantage for cats on my cats. On one of the cats I had a bad reaction. So be careful not all cats are the same and some are more sensitive than others.

Its important to follow the instructions carefully particularly dosage based on weight. You also need to check that the product is safe for kittens, or pregnant cats or mother cats with kittens. Some products will kill fish so are to be avoided. Pyrethrins are particularly toxic to fish.

Flea control in the cat's environment

Because the eggs drop off the cat hatch and the larva develop in the cat bedding, it is important to treat and clean this area.

Wash bedding and vacuum regularly around the bed and along cracks and crevices where fleas and larvae can hide.

The Vacuum cleaner has another advantage besides just removing eggs and larvae. The noise and vibration of the vacuum cleaner help stimulate the flea pupa to hatch and this makes them easier to kill. The pupa case is quite a safe impermeable capsule and helps protect the flea from insecticides. Once the flea has hatched, it is more exposed and can be killed with more ease.

In extreme cases spraying baseboards and cracks in the floor with insecticides is necessary. Pay particular attention to areas where the pet likes to sit and sleep.

Steam cleaning carpets and upholstery is useful.

Flea larvae don't like light and will go deep in the carpet or under cushions and this makes them more difficult to catch.

Ask your Vet

Talk to your vet for the latest in flea medication. There is a large range of products available and many are quite dangerous to you and your cat (and other pets) if mis-used.

Connecticut Agricultural Experiment Station has an interesting article on fleas.

Images are from Wikipedia

emails: Christine

This article is provided for information only. It is not to be used instead of consulting a VET. If your kitty is sick get some help.