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Hookworms are small, thin nematodes that are approximately 10 to 20 mm in length and are a common intestinal parasitic worm of dogs but can also infect cats.
Hookworms live in the duodenum, the first part of the small intestine, where they use teeth-like hooks to attach to the intestinal wall where they feed on tissue fluid and blood. An adult hookworm can consume up to 0.1 ml of blood every day, changing their point of contact every 4-6 hours. Hookworms inject an anticoagulant into the feeding site to prevent blood clotting, and a heavy infestation can lead to anemia (low red blood cell count) due to blood loss.
Types of hookworms
The most common types of hookworms to infect cats are Ancylostoma and Uncinaria, of which there are several species:
- A. ceylanicum
- A. braziliense
- A. tubaeforme
- U. stenocephala
Hookworm eggs pass into the environment via the cat’s stool. Depending on conditions, within 2 – 5 days these eggs hatch into infective larvae (immature worms). At this point, they can infect a passing cat.
- Skin penetration (percutaneous): When a cat comes into contact with an environment infected with hookworm larvae which can penetrate the skin, from there, they migrate to the intestine where they mature.
- Ingestion or inhalation: Cats can also become infected by ingesting infective third stage larvae of uncinaria in the environment, during grooming or via contaminated water and food.
- In utero: Worm eggs may be passed on from mother to her unborn puppies via the placenta. It hasn’t been established if this is the case with feline hookworms yet.
- Transmammary: Again, in dogs, it is possible to pass hookworm to puppies via the breast milk. When a dog becomes infected with hookworms most of them migrate to the small intestine. However, some enter other tissues of the body, where they remain dormant for years. During pregnancy, they reactivate, migrate to the mammary glands and out through the milk. It hasn’t been established if this is the case with cat hookworms yet.
Once the cat comes into contact with infective larvae, they travel to the small intestine where they hook onto the wall and mature. Mature hookworms lay hundreds of eggs which pass out of the body via the feces. Hookworm eggs can survive for an extended period in the environment.
Symptoms of hookworms vary depending on the severity of infection and the type of hookworm involved. Some cats will remain asymptomatic. Common symptoms include:
- Dark, tarry stools
- Pale mucous membranes due to anemia
- Poor coat condition
- Skin irritation, especially on the feet where hookworm larvae penetrate the skin
- Weight loss
- Stunted growth in kittens
The veterinarian will be able to diagnose hookworm via fecal flotation. A stool sample from your cat is mixed with a liquid solution, any eggs present in the feces float to the top which are collected and viewed under a microscope to determine the type (hookworm, roundworm etc.) as well as the number of eggs present.
Hookworms are more prevalent in dogs than they are in cats, and when cats do have them, they are more likely to be in smaller numbers. Treat any worm infestations immediately. As hookworms feed on the cat’s blood, cats can become anemic. Adult cats are more resistant to hookworms than kittens.
There are several effective medications available to treat hookworms in cats. Your veterinarian will be able to recommend a suitable product. Most worming medications are available in topical (applied to the skin on the back of the neck) or tablet form.
Medications are only effective against adult hookworms. Therefore a repeat treatment at 2-3 week intervals will be necessary.
Severely infected kittens may require hospitalisation and blood transfusions to treat anemia.
Even indoor cats are at risk of infection as eggs can be transported into the house on footwear.
You can, although they can’t develop into the adult form as they do in cats. The infective larvae are found in the soil or sandy areas such as beaches or children’s sandpits and can penetrate the skin. From there they migrate beneath the surface, causing a red, itchy skin eruption. Commonly affected areas are hands, feet, between the toes and buttocks however they can migrate to the eyes, causing blindness, this condition is known as Cutaneous Larva Migrans (also called creeping eruption or ground itch). Hookworm larvae cannot complete their life cycle and die in the epidermis.
- Maintain a regular worming schedule as per instructions on the brand you are using. Worm all cats in the house at the same time.
- Remove feces from litter trays twice a day.
- Preventing hunting in cats.
- If you do allow your cat to go to the toilet in your garden if they do clean up any feces quickly.
- De-worm female cats two weeks before breeding and administer another dose late in pregnancy.
- Worm kittens from two weeks and every two weeks until they are 12 weeks old.
Adults and children should avoid walking barefoot in areas which have been defecated in by animals.