Cat Fleas: Identification, Life Cycle, and Treatment

Fleas! The one word no one wants to hear. These tiny little insects make everyone in the household miserable. Fleas are not only a nuisance, making your pet itchy and uncomfortable, but they can cause serious health problems and spread diseases.

The Cat Flea

While over 2000 species of fleas have been identified, Ctenocephalides felis, or the common cat flea, is by far the most common flea in domestic mammals, causing 95% of flea infestations of dogs and cats. The dog flea, Ctenocephalides canis, is much less common but can also infest cats and other mammals.

Fleas are small, wingless insects that can jump up up to thirteen inches – that’s over 100 times their length! They range in size from 1.5 to 4mm, and can be hard to see, which makes flea control rather challenging. Their flat bodies allow them to easily move in between the hairs on your cat.

Because cats are often fastidious groomers, they often swallow fleas as they clean themselves, making it hard to find them. Sometimes when I am closely examining a cat’s skin, I just see a small brown streak scurrying through the fur and wonder “was that a flea?” It can take another five minutes of searching before I see another one.

Causes of Fleas in Cats

Once you understand the complex and long life cycle of a flea, you can understand why it can be so hard to get a flea infestation under control. Because most of the flea life cycle takes place off of the host and in the environment, if one of your pets has fleas, they all likely do. Fleas can jump between hosts, so it’s easy for one pet in the household to pick up a flea when out and about. This flea can then quickly multiply in the home environment and infect other pets.

The adult fleas are only the very tip of the iceberg, accounting for only 5% of the flea population. The remaining 95% are the developing stages that live in the environment. Adult fleas live on your pet where they bite to take in blood meals, reproduce, and lay eggs. A female flea can lay up to 50 flea eggs a day! The eggs and flea dirt fall off your cat into their environment. The eggs hatch into larvae in two to twelve days.

The larvae feed on the flea dirt, grow, and molt over a period of nine to two hundred days. After their third molt, the larvae form pupae, or cocoons, where they develop into an adult flea anywhere between one week and one year, depending on environmental conditions. Once the adult fleas hatch, they can survive in the environment for up to two weeks before they need to find a host (cat, dog, person) for a blood meal.

Symptoms of Fleas in Cats

The main sign that your cat has fleas is usually that they become itchy and uncomfortable. This may present in a few different ways:

• Scratching
• Licking and excessive grooming
• Hair loss
• Red, sore, scabby skin
• Twitching skin
• Unusual behavior such as being more jumpy than normal

You may also be able to find physical evidence of the fleas on your pet.

Complications of Fleas in Cats

Fleas are not just a nuisance, they also carry parasites and diseases. A flea infestation can severely affect your cat’s overall case and may even be deadly.

Fleas Can Transmit Disease

Fleas are the intermittent host to the tapeworm Dipylidium caninum. A cat with fleas will likely ingest a few fleas while grooming. The tapeworm will mature inside the cat’s digestive tract where it steals nutrients from its host.

Fleas can also transmit Yersinia pestis, the bacteria that causes Bubonic Plague. Although we think of the plague as being a disease of the past, it can still be found in the Southwest United States. Fleas are thought to be a vector for another parasite in cats. Hemotropic Mycoplasma spp. are bacteria that infect red blood cells of cats. The infection of the bacteria on the red blood cells causes rapid destruction of the cells and severe anemia that can lead to death.

Anemia

Cats with heavy flea infestations may develop anemia. The fleas feed on blood from the host. If there are enough adult fleas feeding, there can be significant blood loss. Young kittens are at a higher risk than adult cats for severe anemia because of their smaller blood volume. Signs of anemia include weakness, lethargy, and pale gums.

Flea Allergies

Many cats develop a hypersensitivity reaction to flea saliva, resulting in flea allergy dermatitis. Cats who suffer from flea allergy dermatitis are intensely itchy. They may develop small bumps throughout their body, sores and bald spots from constant licking and scratching, and secondary skin infections. They may develop feline eosinophilic granuloma complex in which open sores develop on the skin and in the mouth of cats.

Cats with flea allergies are so sensitive that the bite of just one flea can cause a severe reaction. In these sensitive cats, year round flea prevention is especially important.

Diagnosis of Fleas in Cats

Fleas are small, but you can find them, or evidence of them, on an infected cat. If you suspect your cat has flea problems, start by looking along the back, just above the tail head. This is the most common place fleas like to live on a cat. Use a flea comb, which is a small comb with fine and closely spaced teeth, to comb through the fur. If you find a flea, you have your answer.

However, if all you have are small black specks, shake those specks onto a white paper towel or piece of gauze. Run water over the crusts. If they turn a rusty red color, you have flea dirt. Flea dirt is the feces of fleas which is mainly digested blood. The blood is what causes the flea dirt to change to a reddish color when it gets wet. Another identifying characteristic of flea dirt is that it is often in the shape of a C.

If your cat has flea dirt, your cat has fleas.

Treating Fleas in Cats

Although it’s called the cat flea, these creatures will happily feed on other pets in the household, including dogs and rabbits. Therefore all pets in the household should be treated if you find fleas on one pet – and also the home environment. In order to break the flea life cycle, it is advised to treat for a minimum of three consecutive months.

There are a number of flea treatments for cats available over the counter and by prescription, including oral products, topicals (spot ons), and flea collars. Speak to your veterinarian about a flea control product that will suit you and your cat.

Topical products are easy to apply. Examples include Frontline Gold and Revolution, which are both very safe products that will kill fleas for a month. Bravecto is another topical product for use in cats that kills fleas for three months. If your cat likes treats, Credelio is a chewable treatment that lasts for one month. Capstar is another chewable tablet that starts killing adult fleas within an hour. The disadvantage is that Capstar only kills fleas for one day.

In a lot of cases, treating your cat for three months with a veterinary recommended product that kills adult fleas for a month and contains an insect growth regulator – which prevents more eggs from hatching – will be enough to control most flea infestations. But don’t forget, there are still eggs, flea larvae, and pupae in the environment.

Washing your pet’s bedding in hot water is often enough to kill eggs and fleas in the larval stage. The pupal stage is the safest stage for the flea in development and is almost impossible to kill. Vacuuming your carpets daily will remove any pupa from the environment. Make sure you empty your vacuum canister immediately after vacuuming, seal the garbage bag, and put the vacuum bag outside so that the pupae can’t hatch and crawl out of the vacuum, only to re-infest your cat. Environmental treatments, such as room sprays can also help kill adult fleas.

If you are unsure if a product is safe for your cat, always call your veterinarian before applying. Before applying a topical flea product, read the label carefully. Some of the products that are safe for dogs contain high levels of permethrins, an insecticide that can cause neurologic effects in cats, including tremors, seizures, and death.

Although there are lots of safe and effective products to treat fleas, there are also many treatments that do not work. Feeding your pet garlic, brewer’s yeast, tobacco, apple cider vinegar, or other “natural” remedies are not only ineffective but can also be harmful to your cat.

How To Prevent Fleas in Cats

Treating a flea infestation is a lot of work, but preventing fleas is easy. If used regularly, the topical treatments I discussed earlier (Frontline Gold, Revolution, and Bravecto) kill fleas on your cat within hours, before they have a chance to feed and lay eggs, saving you and your pet months of discomfort.

Capstar is a good preventative if your cat may have had limited contact with another animal with fleas, such as at the groomer. Capstar works quickly to kill the adult fleas before they have a chance to lay eggs and infest your kitty.