How can my cat get fleas?
Fleas can spread directly from a flea-infested animal to your cat, but usually cats get fleas from their environment.
Fleas live, feed, and mate on many animals, including cats, dogs, rabbits, ferrets, opossums, rodents, and raccoons. Flea eggs fall off these animals, into the environment, where they hatch into larvae. The larvae eat organic debris until they mature into pupae (the stage within a cocoon). The pupae may lie dormant for weeks to months, awaiting the ideal environmental conditions before hatching into adults.
Newly hatched adult fleas jump onto a host animal to complete their life cycle. Within two days of eating a blood meal from the host and mating, the female flea begins to lay eggs, which then drop off into the environment, and the cycle starts again, spreading fleas to more animals. Under ideal conditions, the flea can complete its entire life cycle in as little as two weeks; in adverse conditions, the cycle can take as much as a year.
The most important source of cat fleas is newly emerged adult fleas in your house or yard. Homes with carpets and central heating provide ideal conditions for the year-round growth of fleas. The highest numbers of flea eggs, larvae, and pupae are found in areas of the house where pets spend the most time, such as their beds and furniture.
Even if fleas are in your house, you probably will not see them. The eggs are tiny, white specks the size of dust particles, while the larvae are somewhat larger, with dark heads and lighter bodies. They migrate deep down into carpets, furniture, or cracks in floors, away from the light.
How do fleas affect my cat?
Many cats live with fleas but show minimal signs. However, some cats are allergic to flea bites, and they will groom or scratch excessively after being bitten, often developing skin infections. Hair loss and scabbing may appear, often at the base of the tail, but it can occur all over the body. Your veterinarian may recommend flea control even when no fleas are found, since fleas are the most common reason for itching and skin infection, and the evidence is often groomed off by your cat.
You may notice small bits of black material within the haircoat. These black specks are bits of flea excrement (“flea dirt”), which is digested blood. A single adult flea consumes many times its weight in blood over its lifetime. If a debilitated or older cat, or a kitten, has a lot of fleas, the blood loss can be severe, resulting in anemia.
Fleas also act as an intermediate host for one species of tapeworm, which means the tapeworm must complete part of its life cycle within a flea. Flea larvae become infected by eating tapeworm eggs. If a cat swallows an infected flea while grooming, the tapeworm larvae will develop into an adult tapeworm inside the cat. Any cat with fleas is likely to also have a tapeworm infestation.
How do I treat my cat if she has fleas?
Ask your veterinarian what they recommend. Many flea-control products are available, such as oral and topical preparations, shampoos, sprays, and powders; however, over-the-counter products may have limited effectiveness. Flea shampoos and powders kill fleas on your cat at the time of application, but they have little lasting effect, so your cat may have fleas again the next day. In general, cats strongly dislike being sprayed, so many cat owners prefer to use topical or oral flea products. Some flea collars can be effective and convenient, but some may be harmful and cause a skin reaction or rash, especially those with a strong pesticide smell.
There are very effective products designed to be administered once per month or once every three months. Some of these products are conveniently combined with medications to prevent ticks, heartworm, and intestinal worms, and are available through your veterinarian. Some products contain adulticide ingredients (kills adult fleas) that remain active between scheduled doses, while others contain insect growth regulators (IGRs) that prevent the larval stages from maturing. Newer products have the combined advantages of adulticides and IGRs and are available through your veterinarian.
ALWAYS READ THE LABEL CAREFULLY. Apply the product as instructed and repeat at the intervals stated. Ensure that the product is labeled for use in cats, as some dog products may be poisonous to cats.
How do I treat my home environment?
Several products are available to kill the adult and larval stages of fleas and stop the flea life cycle, such as:
- Adulticide sprays for use in the house
- Sprays containing IGRs for use in the house
- Insecticides applied by professional pest control companies
Sprays should be used in places where the flea eggs, larvae, and pupae are likely to be. Treat the entire household first and then concentrate on the hot spots — your cat’s favorite napping spots, such as soft furniture, beds, and carpets. Once larvae hatch from the egg, they move away from the light and burrow deep into carpets and other nooks and crannies where they are difficult to reach. Be sure to move cushions, furniture, and beds to spray under them. Larvae are also likely to live in baseboards and the cracks and crevices between floor seams or floorboards.
Flea eggs and pupae are extremely tough and resistant to insecticides. To remove eggs, as well as dead fleas, wash your pet’s bedding in hot water or replace it. Regular and thorough vacuuming of your carpets, floors, and soft furnishings can remove many flea eggs, larvae, and pupae. You will need to throw away the vacuum bag to prevent eggs and larvae from developing inside the vacuum cleaner. It is helpful to vacuum before using a spray for the house because the vibrations will encourage newly developed fleas to emerge from pupae and be killed by the insecticide.
Should I treat outdoor areas where my cat spends a lot of time?
Flea exposure is inevitable when your pet goes outside, so cats that go outdoors should receive a veterinary-recommended flea preventive year-round. Another way to reduce flea exposure is to discourage other animals like raccoons and opossums from spending time in your yard. Bear in mind that your cat may be going into other people's houses if they are allowed to roam outdoors.
If your yard is heavily infested, you can consider spraying a product containing an IGR and repeating every 14–21 days for three to five applications. Concentrate on shaded areas, storage sheds, cars, and any outdoor sleeping spots. It’s important to note, however, that these sprays may have a negative effect on other insect populations outdoors.
Are insecticides safe for my cat and my family?
Insecticides for flea control should be safe for pet dogs, cats, and humans, if the manufacturer's instructions are followed. Avoid combining insecticides without consulting your veterinarian. Always tell your veterinarian about any flea control products you are using apart from those prescribed. When flea control products are used properly, side effects are rare and do not affect all cats.
Certain types of pets may be susceptible to some products (e.g., birds, fish, amphibians, reptiles, and invertebrates). Avoid using any flea control products in the room where these pets are kept without first consulting your veterinarian.
I noticed my cat had fleas after she returned from boarding. Did she get fleas there?
Not necessarily. Pre-adult fleas (pupae) can survive for many months in their protective cocoons. When you or your pets are absent from home for extended periods of time, these pupae remain in the cocoons because no host is available. As soon as you or your pet return home, adult fleas emerge in large numbers and jump onto cats, dogs, and even people in the search for a blood meal. Vibrations (from walking) and/or increased carbon dioxide (from breathing) trigger the fleas to emerge from their cocoons.
Why does my cat still have fleas after treating her and the environment?
The apparent failure of flea treatment is almost always due to improper application of the preventive, inadequate treatment of the home, or exposure to other infested pets or environments. It is important to continue to administer flea control to all pets in the house for 3–6 months following an infestation to allow time for remaining flea life stages to develop into adults and then be killed when they jump on your pet.
There is no evidence of fleas developing resistance to insecticides, especially once-a-month topical flea preventives that contain a sterilizing agent or IGR in addition to the adulticide. Most flea problems can be overcome by using a veterinarian-recommended flea preventive product regularly on your cat in addition to treating your home.
