Intestinal Parasites of Dogs & Cats

These Worms can Infect Humans too!*

Roundworms – Roundworms are one of the most common intestinal parasites of dogs and cats. As the name suggests, they are long round worms that live in the intestines of our dogs and cats. Roundworms absorb the digested food as it passes through the intestines.

  • Diagnosis – Fecal Centrifugation or Floatation
  • Transmission – Animals and Humans are exposed through soil contaminated with Roundworm eggs. These eggs are passed in the Feces of Infected Animals.
  • They may also become infected by eating infected animals.
  • Puppies are infected by their mother during pregnancy and nursing.
  • Clinical signs – Usually none in dogs and cats. Can see intestinal upset or failure to thrive with heavy worm burdens.
  • Treatment – De-worming medication. Usually needs to be repeated in 1 month. Follow up with negative stool sample 1 month after last dose of medication. You may see worms in your animal’s stool after treatment!
  • Zoonotic Potential (can humans get this?)*: Yes, in humans Round worm infection can cause liver disease, blindness, and other problems. Passed by poor hygiene, fecal-oral transmission. Prevent by good hand washing habits and keeping pets worm-free!

Hookworms – Another common parasite of dogs and cats. Hookworms suck blood in the intestinal tracts of our pets! Hookworms hang onto the intestinal wall using six sharp teeth and drink blood! For this reason, Hookworm infections may be fatal to young puppies!

  • Diagnosis – Fecal Centrifugation or Floatation
  • Transmission – Animals become infected by eating infected soil, or the worms can penetrate an animal’s skin or foot pads. Passed from mother to her puppies during pregnancy and nursing.
  • Clinical Signs – Puppies can be pale, and weak. They may or may not have diarrhea. Adult animals may have these signs or may be asymptomatic.
  • Treatment – De-Worming medication should always be repeated, usually in 1 month, when Hookworm infection is present. Follow up with a negative stool sample 1 month after last treatment.
  • Zoonotic Potential* – Yes, humans may become infected through contaminated soil, from eating contaminated, unwashed produce, or the worm may penetrate skin. The site of penetration is often very itchy.

*Contact your family doctor or pediatrician for more information regarding the Zoonotic potential of these parasites.

Whipworms – Another common intestinal parasite of dogs and cats. Whipworms live in the large intestines of dogs and rarely in cats. They burry their head in the colon wall and suck blood.

  • Diagnosis – Fecal Centrifugation or Floatation. Female worms lay few eggs, it is therefore difficult to find evidence of Whipworm infection and retesting may be required if clinical signs persist.
  • Transmission – Soil contaminated with feces. Very difficult to clean soil of Whipworm eggs.
  • Clinical Signs – Small worm burdens may not cause health problems for the animal. Large numbers of worms may cause severe inflammation of the colon and lead to bloody diarrhea. This can also mimic Addison’s disease (hypoadrenocorticism), a very serious disease that causes waxing and waning illness that can be life threatening.
  • Treatment – De-worming medication. Several doses are needed to clear the infection. Your dog may need to be treated for 2-3 months. Your veterinarian may choose to put your dog on a specific Heartworm Prevention that also controls Whipworm populations.
  • Zoonotic Potential* – Low potential for spread to humans.

Tapeworms – Tapeworms are long flat worms made up of many segments. Their eggs are passed in packets, and are therefore difficult to diagnose on fecal centrifuge/float. Many times they are diagnosed by you at home! If you see little “grains of white rice” on the fur around your animals rear-end, those are Tapeworm segments!

  • Diagnosis – Seeing white segments on fur.
  • Transmission – Intermediate host is needed. Dogs and Cats become infected with Tapeworms by eating Fleas or Rodents.
  • We may be able to tell which by examining the segments.
  • Treatment – De-Worming medication + Flea Control.
  • Zoonotic Potential* – Humans get these the same way our pets do, by eating fleas or rodents.

*Contact your doctor or pediatrician for more information regarding the Zoonotic potential of these parasites.

Coccidia – Single celled organism that infects the small intestines of dogs, cats, and many other animals. It is most common in young animals. The organism divides inside the cells lining the intestines, when there are many organisms, the cell breaks open releasing the Coccidia into the intestines.

  • Diagnosis – Fecal float or Centrifugation.
  • Transmission – Soil contaminated with feces, or ingesting infected rodents. More common in areas with a dense population, may be a sign of poor hygiene.
  • Clinical Signs – Watery, bloody diarrhea.
  • Treatment – We do not have drugs that directly kill the organism. However, we have medications that will stop Coccidia from reproducing, and the animal’s immune system will take care of the rest. A recheck fecal exam in recommended 1 month after treatment.
  • Zoonotic Potential* – Humans may become infected with a Different Species of Coccidia than dogs or cats are susceptible to.

Giardia – A protozoan parasite that is infectious to both humans and pets. Giardia is very motile thanks to many flagella (whip-like structures that help it to move) and lives in the small intestines of humans and pets. Once in the intestines, it attaches to the wall with a suction cup-like structure. Giardia is thought to cause problems with normal intestinal absorption of vitamins and other nutrients.

  • Diagnosis – Can be found on routine fecal centrifugation, however, usually a special test on fresh feces is needed for diagnosis. Because the organism is not consistently shed in feces, re-testing may be needed.
  • Transmission – Contaminated water is the main source for our pets and for us. More common with dense populations of animals.
  • Clinical Signs – Watery diarrhea. Not generally bloody. Can be mild or severe, intermittent, chronic, or acute.
  • Treatment – There are several drugs used to treat Giardia infections. Your veterinarian will decide based on the severity of infection and health of your animal. Different treatments may need to be used and re testing is needed to verify that infection is cleared.
  • Zoonotic Potential* – Humans become infected from contaminated water also. May or may not be related to animal’s infection. Fairly common human infection.

*Contact your doctor or pediatrician for more information regarding the Zoonotic potential of these parasites.

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