Common Parasites in Dogs: A Comprehensive Guide

Understanding the Parasites Inside Dogs

What Types of Parasites Live in Dogs?

1. Tapeworms

Tapeworms are segmented parasites that absorb nutrients from their host through their permeable surfaces. They attach to the intestinal mucosa using their scolex, which is the head of the worm. Mild infections often go unnoticed, but severe cases can lead to hemorrhagic enteritis. Dogs may exhibit symptoms like hyperactivity, tetany, or paralysis. The shedding segments can irritate the anus, causing itching, pain, and behaviors like sitting and rubbing the tail base, leading to hair loss.

2. Hookworms

Hookworms have three sharp teeth in their mouth that allow them to firmly attach to the host's intestinal villi. They feed on the blood from the bite wounds, leading to symptoms like melena (black stools) and abdominal pain. Chronic bleeding can cause anemia.

3. Coccidia

Coccidia are microscopic parasites that live in the host's small intestine. They multiply and damage the cells in the mucosal lining. Puppies are particularly susceptible, and symptoms can include diarrhea, sometimes with blood, as well as malabsorption, anemia, and weakness.

4. Whipworms

Whipworms, also known as Trichuris vulpis, have a thick front end, a thin middle, and a thick rear end. They penetrate the cecum's mucosa and live in the deeper layers. They absorb blood and plasma, and they also digest red blood cells for nutrients. Severe infections can lead to chronic diarrhea, mucoid stools, and a foul odor.

5. Toxoplasma gondii

This protozoan parasite can infect a variety of animals, including dogs, cats, and humans. It requires the oocysts from infected cat feces to develop externally for 12 days before becoming infectious. Toxoplasma can spread throughout the dog's body, affecting the brain, heart, and eyes, leading to a weakened immune system. While most infections are asymptomatic, they can cause symptoms such as fever, cough, difficulty breathing, decreased appetite, disorientation, increased nasal and ocular discharge, vomiting, pale mucous membranes, motor impairment, premature birth, and abortion.

Pet Doctor's Tip: For more information about dog parasites, check out our article "Pet Common Internal Parasites".