Internal Parasite Prevention Month: Hookworms

When compiling a list of the top internal parasites of cats and dogs, hookworms are right up there with roundworms! In honour of Internal Parasite Prevention Month, we at Central Veterinary Services wanted to share some important information about hookworms with you!

The life cycle of the hookworm starts with the egg being found in contaminated soil. With warmth, the L1 larvae molts to a L2 larvae, which then molts to a L3 larvae. The L3 larvae is then swallowed (sometimes during self grooming), or may penetrate the hosts intact skin. The L3 larvae then migrates through the blood and body tissues to the lungs where it is coughed up, and then swallowed. Once in the small intestines the hookworm larvae matures to an adult hookworm. The adult hookworm attaches itself to the villi of the small intestine where it will feed on the hosts blood, and secrete an anticoagulant. The adult female hookworms begin to produce eggs which are then excreted in the hosts feces to begin the life cycle once more. Like roundworms, hookworms may also be transmitted via the trans-mammary and trans-placental routes to neonates. 

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Hookworms are a lot nastier than roundworms since they have up to three pairs of ventral teeth with which they attach to the mucosa of the small intestine. These parasites also enjoy changing attachment sites therefore leaving their former attachment sites bleeding. The hookworms voracious feeding activity, and hemorrhage from former attachment sites often causes anemia in the host. Along with anemia, some other common symptoms of hookworms are dark feces (due to digested blood), unthriftiness in puppies or kittens, and in some cases diarrhea. 

So, for the reasons above, us at Central Veterinary Services believe in deworming all puppies and kittens during their initial visit to the clinic. It is also recommended for dogs and cats to get yearly fecal examinations done (including a fecal smear and a fecal flotation) to ensure they have not been infected with this parasite from the environment. Many heartworm prevention medications are also labelled for use against this parasite (and possibly others) therefore ensuring your pet is roundworm free!

Some types of hookworms can infect humans by penetrating the skin, or by direct ingestion. This is most likely to occur when walking barefoot on a beach, or in other areas where animals defecate. Infection often results in an itchy sensation. It is advised to wear shoes when walking on beaches, and/or in other areas where animals are allowed to defecate. It is also important that children not be allowed to play in areas where animals defecate to prevent transmission of this parasite. If you come in contact with contaminated soil and/or feces wash your hands immediately. 

If you have any questions about roundworms, or any other internal parasites don't hesitate to call us at 204-275-2038. One of our Veterinarians, or Registered Animal Health Technologists would be happy to assist you. 


  • The Merck Veterinary Manual Eleventh Edition