Hookworms in Cats

If your cat has been diagnosed with hookworm, you may be concerned about what this means for your pet. Hookworms are a common intestinal parasite in cats and dogs, causing symptoms such as diarrhea, vomiting, and anemia. However, most infected cats are asymptomatic and infections are often only identified on routine screening tests. Fortunately, hookworms are treatable, but there are some things you’ll need to know about hookworms to keep your cat from getting infected again.

What Are Hookworms in Cats?

Hookworms are a blood-sucking intestinal parasite that occurs in cats, dogs, and humans.  Hookworms are a common parasite of cats, particularly those that go outdoors, have access to feral cat populations, hunt, or access potentially contaminated environments. The most common species of hookworms in cats are Ancylostoma tubaeforme and Ancylostoma braziliense. Once infective larvae of these species reach the cat’s GI tract, they mature into adult hookworms that firmly attach to the intestinal wall via six sharp teeth. Adult hookworms can live in the intestine for four to 24 months, living off the host’s blood. Large hookworm infestations can lead to anemia and death, especially in young animals.

What Causes Hookworms in Cats?

Any age or breed of cat can be infected with hookworms, but young cats are more likely to be affected. Cats get infected with hookworm in several ways. One of the most common ways cats become infected with hookworm is through ingesting infective larva from the environment. This can occur from ingesting contaminated feces or soil. The hookworm larvae are swallowed and travel to the gastrointestinal tract, where they mature into adults.  

Cats can also acquire hookworms from eating infected prey such as rodents. Cockroaches, in particular, are a very common transport host of hookworm larvae. When the cat ingests the cockroach, the dormant larvae are released into the cat’s digestive tract, where they develop into adult hookworms.

Hookworms can also be transmitted just by walking in areas contaminated with infective hookworm larvae. The larvae can penetrate the skin, after which they travel to the lungs via the cat’s veins and lymphatic system. The larvae then migrate through the lungs to the trachea.  Large numbers of migrating larvae can cause respiratory symptoms and pneumonia. Once they reach the trachea, the larvae are coughed up and swallowed, allowing them to reach the digestive tract where they mature into adult hookworms.

Hookworms in dogs can be transmitted from mother to puppies before birth and during nursing. This does not occur in cats.  

It is important to note that the same cat can become infected with hookworms more than once.  Cats can become re-infected from the environment and infective hookworm larvae can survive in soil for a few months under optimal conditions. Infected cats also shed hookworm eggs in their feces, further contaminating the environment. Practicing good sanitation by removing and disposing of feces promptly is essential to reduce the risk of re-infection.

Humans can also become infected with hookworms from the environment. This typically occurs by ingesting contaminated soil, most often occurring in children who play in areas where infected cats or dogs defecate. Humans can also be infected via direct skin penetration of the infective larvae. Direct transmission of hookworms from cats to humans does not occur.

Symptoms of Hookworm in Cats

Many cats infected with hookworm are asymptomatic and do not show any signs of infection, so routine screening tests are important to identify hookworm infections. In kittens, heavy infestations of hookworms may cause anemia and death. Other symptoms of hookworm infection can include:

• Blood in the stool
• Diarrhea
• Constipation
• Vomiting
• Dry cough
• Poor hair coat
• Pot-bellied appearance
• Loss of body condition
• Loss of appetite
• Pale mucous membranes
• Respiratory symptoms
• Pneumonia
• Failure to thrive

If you suspect your cat may have hookworms, or any other type of parasite, visit your veterinarian to diagnose the problem and receive appropriate treatment.

How to Diagnose Hookworm in Cats

If a hookworm infection is suspected, your veterinarian will first perform a full head-to-tail physical examination on your cat. Your veterinarian may also recommend additional diagnostic testing, such as the evaluation of a fecal sample. Your cat’s fecal sample may be used for the following tests:

• Fecal floatation with centrifugation. This test is used to look for parasite eggs in your cat’s feces. A female hookworm produces 600-6,000 eggs per day, which are passed in the feces. These microscopic eggs float readily in a floatation solution and can then be visualized under a microscope. Identifying hookworm eggs on a fecal floatation test confirms the presence of hookworm infection in your cat.
• Fecal antigen testing. This test identifies an antigen produced by both immature and adult hookworms in the small intestine. This test does not rely on egg production, so it can detect hookworm infections by immature worms or those that are single-sex infections, allowing earlier identification and treatment. Because each test has its strengths and weaknesses, fecal antigen testing and fecal floatation testing are typically performed together.

Hookworm Treatment for Cats

If left untreated, hookworm infections can lead to anemia, respiratory illness, loss of body condition, failure to thrive, and even death, particularly in young animals. Hookworm infections should be treated immediately with deworming (anthelmintic) medications to kill the adult worms. In severe infections, additional supportive care such as fluids, blood transfusions, iron supplements, or a high protein diet may be needed to support the animal until the worms are killed. Your veterinarian will determine the best course of treatment based on your cat’s test results and the severity of the infection.

In addition to medication to kill the worms, it is important to practice good environmental sanitation to prevent re-infection. Because hookworm eggs are shed in the feces, frequent removal and disposal of feces from the environment is essential to prevent re-infection. Following treatment with anthelmintic medications, repeat fecal floatation tests are necessary to ensure that hookworm eggs are no longer being shed.

Hookworm Medication for Cats

Anthelmintic dewormers are used to kill adult hookworms and treat hookworm infections. These include medications such as:

• Ivermectin
• Selamectin
• Moxidectin/Imidacloprid 
• Fenbendazole 
• Milbemycin oxime
• Emodepside
• Selamectin/Sarolaner
• Pyrantel pamoate

General Cost of Hookworm Treatment for Cats

In most cases, two rounds of deworming medication are recommended to clear a hookworm infection. In severe infections, additional medications and supportive treatments may be necessary, which will incur an additional cost. For the average hookworm infection, cat owners should expect to pay around $25-$150 for treatment, depending on the medications prescribed.

How to Prevent Hookworms in Cats

The best way to prevent hookworm infections is by deworming kittens with an age-appropriate anthelmintic deworming medication at 2, 4, 6, and 8 weeks of age. All cats should also be started on a monthly preventive medication as soon as they are old enough to do so.

Environmental sanitation is also an important step to prevent infection and especially to prevent re-infection after a cat has tested positive for hookworms. Feces should be removed from the litter box or the environment and disposed of promptly. This prevents hookworm eggs from hatching and larvae from developing.  

Related Conditions

• Roundworm
• Tapeworm
• Whipworm
• Coccidiosis