Giardia in Dogs: Care, Causes & Treatment (Vet Answer)

Giardia in Dogs: Causes, Symptoms, Treatment and Prevention

If your dog has been experiencing bouts of diarrhea, Giardia may be the culprit. Giardia is a microscopic parasite that commonly infects the intestinal tracts of dogs and other mammals, leading to an illness known as giardiasis. Many dogs infected with Giardia show no signs at all, but can still pass the parasite to other animals and even humans. So it‘s important to understand how Giardia spreads, what symptoms to watch for, and the necessary steps for treatment and prevention.

What Is Giardia?

Giardia is a single-celled protozoan parasite that infects the small intestine. There are several species of Giardia, with Giardia duodenalis (also known as G. intestinalis or G. lamblia) being responsible for illness in both dogs and humans. This sneaky parasite has a two-stage life cycle:

1. Trophozoite: The active feeding form that attaches to the intestinal wall and causes damage, leading to symptoms. Trophozoites cannot survive outside the body.

2. Cyst: The infective stage that is passed into the environment via feces. Giardia cysts have a protective outer shell that allows them to survive for weeks to months in cool, damp environments until ingested by a new host. Once inside the digestive tract, the cyst wall breaks down and releases the trophozoite, starting the cycle anew.

Many dogs infected with Giardia never show any signs of illness, but still shed microscopic cysts into the environment in their feces. These asymptomatic carriers make giardiasis tricky to control, as they can silently spread the parasite to other dogs and contaminate shared spaces like dog parks, kennels, and yards.

How Do Dogs Get Giardia?

Giardia spreads through the fecal-oral route, meaning a dog becomes infected by ingesting cysts shed in the stool of another infected animal. This can happen through direct contact, such as sniffing or licking contaminated feces. However, the hardy cysts can also contaminate water, food, soil, and surfaces, remaining infective for months in the right conditions.

The most common sources of Giardia infection for dogs include:

• Drinking from contaminated puddles, ponds, or streams
• Playing in contaminated water
• Eating grass or soil where infected feces were present
• Licking their paws/fur after walking through a contaminated area
• Sniffing or eating the feces of an infected dog
• Exposure to high-risk environments like overcrowded kennels, shelters, or breeding facilities

Puppies, senior dogs, and those with weakened immune systems are at higher risk of illness if exposed. However, even healthy adult dogs can experience symptoms or become asymptomatic carriers.

What Are the Symptoms of Giardia in Dogs?

Giardia damages the intestinal lining, causing inflammation and interfering with nutrient absorption. However, healthy adult dogs may fight off the infection before symptoms appear. If symptoms do develop, they usually begin within 5-12 days of exposure and can be either sudden or gradual in onset.

The most common signs of giardiasis in dogs include:

• Diarrhea (soft, watery, or greasy stools)
• Straining to poop or mucus in stools
• Increased frequency of bowel movements
• Vomiting or nausea
• Decrease in appetite
• Weight loss
• Lethargy or depression
• Poor coat condition

Symptoms can last for several weeks and may be intermittent. Some dogs will have very mild signs that come and go, while others can develop more severe diarrhea, dehydration, and weight loss. If your dog shows any of these symptoms, it‘s important to consult your veterinarian for proper diagnosis and treatment.

Diagnosis and Treatment

Giardiasis can be tricky to diagnose, as the classic symptoms can also indicate other illnesses like viral infections, bacterial overgrowth, or inflammatory bowel disease. Additionally, Giardia cysts are shed only intermittently in feces, so a single negative fecal test doesn‘t necessarily rule out the parasite.

To diagnose giardiasis, your vet will conduct a physical exam, review symptoms, and analyze a stool sample under the microscope. A fecal ELISA (enzyme-linked immunosorbent assay) test may also be performed to detect Giardia antigens, as this is more sensitive than visual examination alone. In some cases, multiple fecal samples taken over several days may be needed to confirm a diagnosis.

Once giardiasis is confirmed, treatment involves a combination of medication, environmental cleanup, and supportive care:

• Antiparasitic drugs: The most common medications for treating giardiasis include fenbendazole and metronidazole. These are typically given orally for 5-10 days.

• Supportive care: If your dog is experiencing significant diarrhea, additional support like anti-diarrheal medications, probiotics, and a bland, easily digestible diet may be recommended. Severely dehydrated dogs may require fluid therapy.

• Cleaning the environment: On the final day of treatment, give your dog a thorough bath to remove any cysts that may be clinging to the fur. Wash all bedding, toys, and bowls with hot soapy water. Steam clean or use a disinfectant on any surfaces the dog has come into contact with (diluted bleach solution or a product specifically labeled to kill Giardia).

• Fecal rechecks: It‘s important to have your vet recheck a stool sample 2-4 weeks after treatment ends to ensure the infection has fully cleared.

Can Giardia Infect Humans?

While there are different strains of Giardia that typically infect dogs versus humans, there is still a small risk of transmission between species. This means an infected dog could potentially pass Giardia to a human family member, particularly if they are immunocompromised, pregnant, or a young child. However, the vast majority of human giardiasis cases are acquired from other human sources, not from pets.

To lower the risk of transmission, practice good hygiene such as washing hands thoroughly after handling your dog‘s waste, cleaning up accidents promptly, and wearing gloves when gardening in potentially contaminated soil. Avoid letting your dog lick your mouth or face. If you are concerned about illness, consult your doctor.

Preventing Giardia Infections

Because Giardia is so common in the environment, it‘s impossible to completely prevent your dog from being exposed. However, there are steps you can take to reduce the risk of infection:

• Pick up and dispose of your dog‘s feces promptly, especially in shared spaces like yards or dog parks
• Avoid letting your dog drink from stagnant puddles, ponds, or streams
• Consider installing a water filtration or treatment system if using well water
• Disinfect potentially contaminated areas regularly (dog runs, kennels, etc.)
• Have your dog‘s stool checked at least yearly or if any GI symptoms arise
• Practice good hygiene and always wash hands after handling dog waste or potentially contaminated materials

While giardiasis can be an unpleasant experience for both you and your dog, the good news is that the majority of cases are highly treatable. Prompt veterinary care, along with thorough cleaning and good hygiene practices, can help your dog recover quickly and prevent the spread of this pesky parasite. By staying vigilant and informed, you‘ll be better equipped to keep your canine companion healthy and happy.