Five Parasites That Kill Animals

Both internal and external parasites cause illness or even death in cats and dogs if left untreated, with some more virulent than others. Parasites are contagious and can also infect people, so take your pet to a veterinarian for a proper diagnosis and treatment to eradicate these pests from his system. Preventive medications and proper sanitation of your pet's living space help keep him safe from an initial infestation of many potentially fatal parasites.

  1. Heartworms

    • Spread by contact with infected mosquitoes, heartworms are a common parasite that infests a dog's pulmonary arteries. Dirofilaria immitis is the culprit behind this disease, which causes coughing -- sometimes with blood -- heavy breathing, lethargy and congestive heart failure. Left untreated, the infestation can be fatal. Diagnosis by a veterinarian includes blood tests, chest X-rays and an electrocardiogram. Treatment includes drugs such as melarsomine, milbemycin and ivermectin, and can be difficult due to the possibility of the blood vessels becoming blocked. Preventive medications are recommended to stop an infestation with heartworms from ever occurring.

    Giardia

    • Giardia is a one-celled (protozoan) organism that infects the intestinal tract of both cats and dogs. It is passed through contact with the feces of an infected animal, which contains the young offspring of the parasites created in the body, called cysts. These cysts thrive in water, and any water supply contaminated with feces readily transmits this parasite, which also infects people. Symptoms include foul-smelling diarrhea, weight loss, lethargy and in severe cases, death. After a fecal smear and examination, your veterinarian will administer medications such as metronidazole or fenbendazole until the infestation is cured. A vaccination for giardia exists to treat dogs and prevent this condition.

    Ticks

    • Ticks are external parasites that attach themselves to your pet's skin and feed on his blood. These parasites live in high grass and wooded areas; they are visible to the naked eye. If left untreated, they can cause anemia from blood loss and spread several viral or bacterial diseases, such as Lyme disease, ehrlichiosis, babesiosis and Rocky Mountain spotted fever, all of which can be fatal for your pet. Ticks can also cause poisoning or paralysis, a condition caused by the toxins injected into the skin by the tick when feeding. A veterinarian will carefully remove the ticks manually. Topical medications can be applied to your pet to prevent ticks.

    Coccidia

    • Coccidia, like Giardia, is a type of protozoan parasite that typically infects puppies, kittens and adult animals with a suppressed immune system. The organism is contagious and causes symptoms including bloody diarrhea, loss of appetite, weight loss, vomiting and severe dehydration. Without treatment, the condition can cause death. If diagnosed by a veterinarian through a fecal examination, treatments including sulfadimethoxine and trimethoprim-sulfadiazine prevent the coccidia organisms from reproducing. This allows the animal's immune system to remove them on its own.

    Whipworms

    • Whipworms infest the large intestine and are contracted through contact with soil, food or water infected by the feces of another animal containing the eggs of the worms. These worms feed on a pet's blood and nutrients, causing inflammation of the intestinal wall, which leads to hemorrhaging and bloody, loose stool. Without treatment, these worms can be fatal due to anemia or severe dehydration. Treatments include pyrantel pamoate and ivermectin, given orally.