Giardiasis (Giardia)

Giardiasis (Giardia)

Species: Dog

Breeds Affected: All Breeds (higher risk in puppies and dogs in group housing or unsanitary conditions)

Giardiasis is an intestinal infection caused by the protozoan parasite Giardia. Dogs become infected by ingesting cysts from contaminated water, food, or surfaces (for example, drinking from puddles or streams containing Giardia). Once in the intestines, the parasite causes malabsorption and gastrointestinal upset. Giardia is zoonotic potential (strain-dependent), meaning it can sometimes spread to humans or other animals.

• Many adult dogs show no signs or only soft stools. Symptomatic cases (more common in puppies or stressed dogs) typically have diarrhea that can be acute
• foul-smelling
• soft or watery
• often with a greenish tinge or mucus. The diarrhea may be intermittent or continuous and can contain blood in severe infections. Affected dogs might have weight loss and poor coat condition due to malnutrition. Vomiting occurs in some cases. The dog usually remains alert and eating
• though in heavy infestations appetite might decrease.

Giardia is treated with specific antiparasitic medications and hygiene measures. The most common approach is oral fenbendazole for several days to a week, which is effective in many cases. Metronidazole is another drug that may be used (sometimes in combination with fenbendazole). Supportive care is important for puppies: ensure hydration (fluids for diarrhea if needed) and a highly digestible diet. The environment should be cleaned (disinfect surfaces, bathe the dog to remove cysts from fur) to prevent reinfection. With proper treatment, diarrhea usually resolves in a week or so.

Antiparasitic medications are the mainstay. Fenbendazole (Panacur) is often given for 3–10 days to kill Giardia in the intestines. Metronidazole (Flagyl) is another commonly used medication, dosed for about 5–7 days, which can kill the parasite and also help with diarrhea and any bacterial overgrowth. In refractory cases, a combination of fenbendazole and metronidazole may be used. If diarrhea is severe, additional supportive meds like probiotics or gastrointestinal protectants might be recommended, though the primary cure is antiparasitic therapy. Good sanitation and bathing to remove infective cysts are also part of management.