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The Vampire Within: Hookworm Infection

Among the many kinds of parasites that dogs and cats can be infected with, hookworms are one of the most dangerous because of the silent and insidious nature of the parasite.  Animals infected with hookworms have little to no outward symptoms.  Left untreated, hookworm infection causes anemia, protein loss and damage to the mucosal lining of the intestine.  The canine hookworm in particular is a voracious feeder and can actually kill a puppy.

Hookworms are parasitic nematodes that live in the small intestine of its host.  Cats, dogs and humans can all be infected with various species of hookworm.

Infection occurs through the larval stage of the parasite.  Larva can penetrate the skin through the feet or another part of the skin that is touching the ground.  Larva can also be ingested via contaminated dirt or by eating an infected animal or insect.  Rodents can carry hookworms, and cockroaches can harbor the larva on their bodies.  Once inside the host, the hookworm makes its way to the intestine, where it attaches to the intestinal lining with six sharp teeth.

Some species of parasites absorb nutrients through their skin, but hookworms actually suck blood.  While in the intestine, the worms mate and the female worm produces eggs.  Eggs are passed out of the body along with fecal material.  The eggs mature into the larval form in the environment and are then able to infect a new host.  Hookworm larva thrive in sandy soil and cannot live in clay or thick mud.  Since infection can take place through the skin, beaches routinely ban dogs during peak season to avoid contamination with potentially infected fecal material.

Hooks can also migrate through the body of the host, ending up in the lungs, where they develop further, get coughed up and then swallowed, ending up back in the small intestine.

Pregnant dogs that are infected can pass the parasite to their unborn pups.  The mother can also pass the parasite through her milk.  Cats cannot become infected through pregnancy or nursing.  Most cats that suffer from hookworm infection obtain it through the skin or by eating an infected animal.

Puppies are at a particular risk from hookworms.  Growth requires an enormous amount of red blood cells, and because hookworms actively suck blood from their host, growth in puppies can be severely affected.  The resulting anemia can be grave enough to cause death.

Pets that are positive for hookworms can be treated with several different oral medications.  Puppies and kittens should receive multiple treatments two weeks apart, even if a stool sample is negative, due to the patent period of the parasite’s various stages.

It is also important to note that hookworms are a zoonotic organism, meaning the same parasite that infects a dog can also infect the owner.

The largely silent nature of hookworm infection makes prevention key.

  • Give your dog a monthly preventive.  Oral heartworm pills, such as Sentinel, provide this protection.  The six month injectable, Proheart, also removes hookworm infection.
  • Pick up dog feces immediately and dispose of it.
  • Keep cats indoors.  Cats that go outdoors are significantly more likely to acquire hookworms via hunting and eating other host species.
  • Don’t let your dog wander.  Your own yard is probably okay, but limit or eliminate scavenging activity by leashing your dog or keeping him in a fenced area.
  • Cover children’s sandboxes when not in use.
  • When gardening, wear gloves and shoes.  If your project requires significant time on the ground, sit on a waterproof gardening pad.
  • Electricians, plumbers or other workers who might have to crawl under porches or buildings with potential rodent access should wear long sleeves and long pants.
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