What is fleas?
Updated By PetymFacts checked against official sources on
Quick answer
Fleas are small, wingless, blood-feeding insects. The cat flea, Ctenocephalides felis, is the most common flea on dogs and cats worldwide, and the main flea on dogs studied in India. Fleas cause itching, flea allergy, tapeworm and, in heavy infestations, anaemia in puppies and kittens. Most of the flea life cycle happens in the home.
Also called flea, cat flea, Ctenocephalides felis, flea infestation, flea allergy dermatitis.
Key facts
- The cat flea is the most common flea on dogs and cats around the world, especially in cities. Tropical Council for Companion Animal Parasites
- On stray dogs sampled in India, a subspecies of the cat flea made up 89.6% of fleas found. Parasites & Vectors (2015), University of Melbourne repository copystudy
- Nearly 95% of the flea life cycle happens in the environment, which is contaminated with eggs, larvae and cocoons. Tropical Council for Companion Animal Parasites
- Some animals develop flea allergy dermatitis, a reaction to proteins in flea saliva. Tropical Council for Companion Animal Parasites
- Very heavy infestations in kittens and puppies can cause anaemia. Tropical Council for Companion Animal Parasites
- Pets catch the flea tapeworm by swallowing fleas while grooming. International Cat Care
How do you know if your pet has fleas?
Scratching and nibbling are the usual first signs, and the Merck Veterinary Manual describes crusted, itchy skin over the hips, base of the tail and thighs as classic. You may see the insects themselves, or flea excrement: dark-red specks that dissolve to a reddish-brown colour on a damp paper towel. A pet with flea allergy can react strongly, with hair loss and skin damage from scratching.
A cat that grooms fleas off can swallow them and pick up flea tapeworm, so a flea problem and a worm problem often come together.
What problems do fleas cause?
Fleas are more than an itch.
| What happens | Who is most at risk | |
|---|---|---|
| Flea allergy dermatitis Tropical Council for Companion Animal Parasites | An allergy to flea saliva: intense itching, hair loss and skin damage from scratching | Allergic dogs and cats |
| Anaemia Tropical Council for Companion Animal Parasites | Blood loss from very heavy infestations | Kittens and puppies |
| Flea tapeworm International Cat Care | Picked up by swallowing fleas while grooming | Cats and dogs that groom fleas off |
| Infections in people Tropical Council for Companion Animal Parasites | Fleas on pets can pass some bacteria and tapeworms to humans | Families, especially children |
Why do fleas keep coming back?
Because the fleas you see are only the adults. TroCCAP's tropical guidelines say nearly 95% of the flea life cycle happens off the pet: eggs fall into bedding, carpets, sofa cushions and floor cracks, hatch into larvae that hide from light, and spin cocoons in which an adult can wait for several weeks, even up to a year, until a sitter arrives. A new wave of adults keeps hatching for weeks after the pet is treated.
In India's warm climate this can carry on all year, and TroCCAP says flea prevention in the tropics must be continuous, not seasonal.
How do you get rid of fleas?
Treat every pet in the home, not only the one with fleas, using products licensed for each species; ask your vet which. Never put a dog flea product on a cat: some are toxic to cats. Wash pet bedding, blankets, rugs and carriers, vacuum floors and furniture often, and treat the places the pet sleeps. Keep going with prevention after the fleas are gone, because new adults hatch for weeks.
Going away soon? Tell us your dates.
A checked local sitter feeds, walks and keeps your pet company at home, follows your care sheet to the letter and sends a photo every day. Petym is opening city by city: send your dates and we will tell you when a sitter can take them.
- Meet your sitter first, free
- PAN-checked, first-aid trained
- A photo every day
- Pay through Petym, never cash
Questions owners ask
Can dog fleas live on humans?
- Fleas prefer pets, but Merck notes that newly emerged, unfed fleas bite people as well as pets. Fleas on pets can also pass some bacteria and tapeworms to humans, according to tropical guidelines. Treat the pets and the home together and the bites stop.
How do I check my pet for fleas?
- Part the fur over the hips, tail base and thighs and look for moving insects or dark specks, or brush the pet over white paper. Put the specks on a damp paper towel: if they dissolve to a reddish-brown colour, they are flea excrement, a sure sign of fleas.
Can indoor cats get fleas?
- Yes. Fleas can arrive on another pet or a visiting animal, and once inside, nearly all of the life cycle happens in the home. Tropical guidelines advise year-round protection for cats, using a product made for cats.
Why does my pet still have fleas after treatment?
- Most of the flea population is in the home as eggs, larvae and cocoons, and new adults keep hatching for weeks. Keep treating every pet on schedule, wash bedding, vacuum often and treat sleeping areas. Ask your vet if fleas persist after several weeks.
Keep reading
Related terms
More in vaccines and parasites
- BabesiosisBabesiosis is a disease of dogs caused by Babesia, tiny parasites that live in and destroy red blood cells. It is spread mainly by ticks, and in India one species, Babesia gibsoni, also spreads through dog fights and blood transfusions. Signs are anaemia with pale gums, weakness, jaundice and red or brown urine. Dogs that recover can relapse.
- Booster vaccineA booster is a repeat dose of a vaccine that tops up or confirms a pet's protection. Puppies and kittens get a booster at about 26 weeks after their first course. After that, modern core vaccines for distemper, parvovirus and panleukopenia protect for years, while leptospirosis, kennel cough and most killed vaccines need a booster every year.
- Brown dog tickThe brown dog tick, Rhipicephalus sanguineus, is the most common tick on dogs in the tropics, including India. Unlike most ticks it lives and breeds indoors, in homes and kennels, as well as outdoors. It spreads ehrlichiosis and one form of babesiosis, the infections Indian owners call tick fever, so tick control is needed all year.
- Core vaccinesCore vaccines are the vaccines every dog or cat should have, wherever it lives, because they protect against widespread, serious diseases. For dogs they cover distemper, adenovirus and parvovirus; for cats, panleukopenia, herpesvirus and calicivirus. In India rabies is core for both, and WSAVA also treats leptospirosis vaccine as core for dogs where the disease is endemic.
- DewormingDeworming is giving a pet medicine, chosen by your vet, to kill intestinal worms such as roundworms, hookworms and tapeworms. Puppies can be born with roundworms and catch more from their mother's milk, so deworming starts in the first weeks of life. Some dog and cat worms can infect people, especially children, so regular deworming protects the family too.
- DHPPi vaccineDHPPi is the combined core vaccine for dogs printed on many Indian vaccine cards. The letters stand for distemper (D), hepatitis from canine adenovirus (H), parvovirus (P) and parainfluenza (Pi). DHPPiL adds leptospirosis (L). It is the same vaccine group that US cards call DHPP or DA2PP, and puppies start it at 6 to 8 weeks.
- EhrlichiosisEhrlichiosis is a disease of dogs caused by Ehrlichia canis, a bacterium carried by the brown dog tick. Signs appear 1 to 3 weeks after infection: fever, dullness, bleeding such as nosebleeds or bruising, and enlarged lymph nodes. Some dogs seem to recover but carry the infection silently and later develop a severe chronic form.
- Flea and tick preventionFlea and tick prevention means regularly protecting a pet from these parasites with a product your vet recommends, plus checking the coat and treating the home. Tropical guidelines say dogs and cats in places like India should be protected all year, including indoor pets. Use products licensed for the species, and never put a dog product on a cat.
- FVRCP vaccineFVRCP is the core combined vaccine for cats. It protects against feline viral rhinotracheitis (herpesvirus), calicivirus and panleukopenia. Indian cards often show a brand name from the vial sticker instead, such as Tricat. Kittens start at 6 to 8 weeks, with doses every 2 to 4 weeks until 16 weeks or older, then a booster at about 26 weeks.
- HeartwormHeartworm, Dirofilaria immitis, is a long worm that lives in the heart and lung blood vessels of dogs and, less often, cats. It is spread by mosquito bites and is widespread in tropical regions, including parts of India. Signs include coughing, tiring on exercise and weight loss. It can be prevented, and dogs should be tested yearly.
Keep exploring
Sources
Each source was opened and read on the date shown. How Petym checks its sources
- Tropical Council for Companion Animal Parasites: Guidelines for the control of ectoparasites of dogs and cats in the tropics (2022) (opens in a new tab)
- International Cat Care: Fleas and flea control in cats (opens in a new tab)
- Merck Veterinary Manual: Fleas of dogs (opens in a new tab)
- European Scientific Counsel Companion Animal Parasites (ESCCAP): GL3: control of ectoparasites in dogs and cats (7th edition, 2022) (opens in a new tab)
- Parasites & Vectors (2015), University of Melbourne repository copy: Rickettsia sp. genotype RF2125 and Ctenocephalides felis orientis infesting dogs in India (stray dogs) (opens in a new tab)