Vet with stethoscope checking a kitten.


The hookworm (Ancylostoma, Uncinaria) is another type of parasite that inhabits the small intestine of dogs and cats. Unlike the roundworm that floats unattached within the intestinal lumen, absorbing nutrients through its skin, the hookworm actually has teeth, which it uses to attach itself to the wall of the intestine.

Once attached, it begins to suck blood from vessels within the wall. In fact, the infestation can become so severe that anemia and eventual death of the host animal could result if the hookworms are left unchecked.

Compared to roundworms, hookworms are fairly small and threadlike, measuring up to 1 inch in length. Their life cycle begins with adult worms within the gut laying eggs, which are then passed out in the stool. If environmental conditions are warm and humid enough, the eggs hatch and give rise to larvae, which then search for a host.

Once a host comes along, the larvae can gain entrance into the body in a number of ways. They can be picked up by way of the mouth, or they can actually penetrate the skin (usually the footpads) and migrate through tissue before reaching the small intestine.

Like roundworms, some of these migrating larvae might decide to stop and settle for a while within the tissues, making it possible for offspring of such females to become infected while still in the womb, or through nursing infected milk. As a result, puppies and kittens can be born with these blood-sucking parasites.

The severity of clinical signs depends largely on the amount of worms present in the gut and the age of the pet infected. Generally speaking, the young suffer from more severe disease than do adults. Lethargy, loss of appetite, and pale mucous membranes due to loss of blood are not uncommon in pets harboring a large worm burden.

A dark, tarry diarrhea may be present. If skin penetration has taken place, the footpads or other areas might be reddened, bleeding, and/or infected because of the larvae. Intense itching can also be noted as a result of this penetration.

Diagnosis of a hookworm infestation is based on an examination of a stool sample for the presence of hookworm eggs. There are a number of safe dewormers available from veterinarians that can help eliminate a hookworm infection.

After the initial dose is given, a follow-up deworming should be administered 2 to 3 weeks later to kill any migrating larvae that have since reached the intestines. In dogs and cats suffering from anemia, supportive veterinary care is needed.

This might include blood transfusions if the loss of blood is severe enough. Intravenous fluids and antibiotics might also be used to combat dehydration and secondary infections. Vitamin and iron supplements, combined with a high-quality diet, are fed to provide building blocks within the body for new blood to be produced.

It is known that some dogs and cats can actually develop an immunity to hookworms after an initial infection has taken place. However, this does not preclude routine periodic stool checks by a veterinarian, since those individuals that actually develop immunity can be difficult to identify.

Hookworm eggs are not as hardy as their roundworm counterparts; hence, environmental control can be an effective way to prevent reinfection or spread to other dogs and cats. Since the eggs require optimum environmental conditions before hatching will occur, keeping fecal material picked up daily in and around the premises will reduce chances of exposure.

Studies have also shown that outdoor dogs kept on concrete stand less chance of infection than do dogs housed in kennels with dirt or grassy floors. Again, this is assuming that daily removal of contaminated fecal material is performed. Deworming female dogs and cats prior to pregnancy will help reduce the chances of puppies and kittens being born with hookworm infections.

However, because deworming will not eliminate larvae within the mother’s tissues and mammary glands, all neonates should be routinely dewormed for these parasites starting at 3 weeks of age. Most heartworm preventive medications on the market today also help prevent hookworm infestations if given on a regular basis.

In those instances where environmental contamination is difficult to control, administering such a preventive year-round is one way to keep a pet hookworm-free. Some hookworm larvae have the ability to penetrate human skin, causing severe itching and dermatitis.

This condition in humans is known as cutaneous larva migrans, or “creeping eruption.” It is seen most often in tropical climates and in the southeastern portions of the United States. Since hookworm larvae thrive in warm sandy soils, this disease is one major reason why pets are denied access to most public beaches.