What is giardia in puppies?

Giardia is a single-celled parasite that lives in your dog's intestine. It infects older dogs but more frequently infects puppies. Dogs become infected when they swallow Giardia that may be present in water or other substances that have been soiled with feces.

Giardiasis is a common parasitic infection that can cause diarrhea in dogs. It is caused by an intestinal parasite called Giardia, which can be found in feces-contaminated soil, food and water.

Some dogs infected with Giardia may not show any signs of infection, but younger dogs or dogs with weakened immune systems are more likely to experience symptoms. It is very easy for dogs to reinfect themselves with Giardia, so successful treatment relies on effective anti-parasitic medications, cleaning and managing the surrounding environment — both indoors and outdoors.

Dogs get Giardia from ingesting feces-contaminated water, soil, food or objects. Giardia has two forms: trophozoites, which live in the intestines of infected dogs, and cysts, which are trophozoites protected by an outer shell and that get shed in the dog’s stool.

Cysts are hardy and can survive in the surrounding environment for months. They are instantly infectious, and just a few ingested cysts can cause infection. A dog could easily get reinfected by grooming themselves, for example, if cysts remain on their fur, paw pads or hind end.

Patients will often be asymptomatic and still have a normal appetite and energy levels. In severe cases, dogs may experience lethargy, decreased appetite or weight loss.

The most common clinical signs of Giardiasis include:

To diagnose giardiasis, your veterinarian will need to examine a stool sample. Because Giardia cysts can be shed intermittently in the stool, they might not be seen on a single stool sample.

Your veterinarian may perform a second fecal test that is unaffected by the intermittent cyst shedding to look for other signs, such as Giardia-specific antigens, which are small proteins produced by the parasite.

The goal of treatment is to resolve diarrhea and other clinical signs. Dogs without symptoms may not require treatment.

With proper treatment, most dogs fully recover from giardiasis.

If diarrhea continues after treatment, your veterinarian may need to recheck a stool sample to see whether your dog has been reinfected. Retesting for antigens is not recommended because Giardia antigens can remain present after an infection has been successfully treated, which may result in false-positives on a test.

Dogs may become reinfected if their surrounding environment is not properly managed. Additionally, if the Giardia is resistant to the medication used or if the medication was not dosed properly, then refractory infections may also occur.

Humans and other species can become infected with Giardia; however, the type of Giardia that normally infects humans differs from the type that infects dogs and cats. (Dogs and cats are also affected by different types of Giardia).

For this reason, it is rare for humans to get infected from a strain of Giardia that pets may carry and vice versa. Regardless, washing hands thoroughly with soap and water after handling pets or infected feces is always important.

If there are multiple pets in the household, a dog infected with Giardia does not pose a risk to a healthy cat because the two species are vulnerable to different strains. Similarly, an infected cat does not pose a risk to a healthy dog.

Giardiasis is an intestinal infection in humans and animals caused by a microscopic protozoan. It is a simple one-celled parasitic species, not a worm, bacteria, or virus. The parasite occurs worldwide and is a common cause of "Traveler's Diarrhea" in people. Outdoor enthusiasts who inadvertently consume contaminated water may develop "beaver fever", another name for giardiasis in people. Other examples of protozoan parasites that can cause enteric (intestinal) disease are Coccidia, Cryptosporidia, and Toxoplasma.

Giardiasis can be a significant cause of illness, especially diarrhea, in animals and people. However, most dogs infected with Giardia do not have diarrhea, vomiting, or any other signs of illness.

The Giardia organism has two forms. A fragile feeding form, known as the trophozoite, exists in the gut of infected animals. A hardy cystic form is shed in feces and can survive several months in the environment, particularly in water and damp environments.

A dog becomes infected with Giardia when it swallows the cyst stage of the parasite. In susceptible dogs, once the cyst passes into the dog's intestines, it transforms into the trophozoite and attaches to the intestinal wall to feed. If sufficient numbers are present, clinical signs of damage to the intestinal wall will develop.

Trophozoites reproduce by dividing, and some transform into the cystic form. Eventually, the dog passes infectious cysts in its stool. The time it takes from ingestion of cysts to passage in feces is 5 to 12 days in dogs and 5 to 16 days in cats.

When Giardia cysts are found in the stool of a healthy adult dog without diarrhea, they are generally considered a transient, insignificant finding. However, in puppies and debilitated adult dogs, they may cause severe, watery diarrhea that may be fatal if left untreated.

The likelihood of developing disease increases when large numbers of cysts are present in the environment from fecal contamination. Giardiasis is common in densely populated environments, such as kennels, pet stores, or animal shelters.

These microscopic parasites attach themselves to the intestinal wall, and the damage causes an acute, sudden onset of foul-smelling diarrhea. Giardia infection in dogs may lead to weight loss, chronic intermittent diarrhea, and fatty stool. The stool may range from soft to watery, often has a greenish tinge, and occasionally contains blood. Infected dogs tend to have excess mucus in their feces. Vomiting may occur in some cases. The signs may persist for several weeks, and gradual weight loss may become apparent.

Diarrhea may be intermittent. Most dogs do not have a fever but may be less active. The disease is not usually life-threatening unless the dog’s immune system is immature or immunocompromised. Many dogs will be asymptomatic carriers, never developing any signs of illness. Younger animals are more likely to exhibit clinical signs.

A routine fecal flotation test may fail to detect these tiny cysts, which are shed inconsistently in the feces and often require a special zinc sulfate flotation solution. Occasionally, the parasites may be seen on a direct smear of the feces. If your veterinarian suspects giardiasis, a stool sample may be analyzed for Giardia-specific antigens (cell proteins). Some Giardia tests are available for in-clinic use, while others require submittal to a reference laboratory. Many cases are presumptively diagnosed based on medical history and clinical signs suggestive of giardiasis.

The most common drugs used to kill Giardia are fenbendazole (Panacur®) and metronidazole. These drugs are usually given for three to ten days to treat giardiasis. Both drugs may be given in combination if necessary. This combination is usually administered to dogs with refractory diarrhea (diarrhea that hasn't responded to treatment). Supportive treatment with other drugs may be needed as supplemental therapy if dehydration or severe diarrhea is present.

A low-residue, highly digestible diet may help lessen loose stools during treatment. Some dogs may require follow-up tests and treatments based on their condition and severity of infection. All infected pets should be re-tested two to four weeks after completion of treatment. Your veterinarian will help determine the treatment best for your pet.

Because Giardia cysts are infective immediately when passed into the environment, feces should be removed quickly and disposed of. Infected animals should be bathed regularly to remove cysts from the hair coat.

Giardia can cause diarrhea in humans and can be passed from dogs to humans. In the past, it was assumed that cats, dogs, and wildlife were an important source of human infection. Genotype A can infect humans, dogs, and cats, while B can infect both humans and dogs.

However, human-to-human transmission is also important, and contaminated municipal water supplies are responsible for many outbreaks.

If your dog is diagnosed with giardiasis, environmental disinfection and good personal hygiene are essential to prevent accidental spread to humans. In particular, people with immunodeficiency, such as AIDS or cancer, or undergoing chemotherapy should use extreme care, especially when handling feces or after administering medications.

For environmental disinfection, you can use chlorine bleach at 1:32 or 1:16 dilutions or 1-2 cups in a gallon of water (60-120 ml/L). However, be sure that the affected surfaces can be safely treated with bleach. Lysol® and quaternary ammonium compounds (e.g., Parvosol®) are also reported to kill cysts effectively. Giardia cysts are susceptible to drying, so keep your environment as dry as possible. For best results, thoroughly clean the pet's living and sleeping areas and then allow the areas to dry out for several days before reintroducing pets.

After speaking with my vet, I realized that Giardia was not limited to foreign countries. The parasite is found all over the world, including in the U.S., but my vet told me not to panic. Luckily, there are many things dog owners can do to prevent their dogs from becoming infected with this unpleasant parasite. Here are the facts about Giardia in dogs you need to know to keep your dogs safe.

Giardia is a single-celled parasite that inhabits the intestines of mammals, birds, and amphibians. There are several different “assemblages” of Giardia, which is the scientific term used to describe the many subspecies of Giardia. Each assemblage targets a specific group of animals, but all Giardia assemblages have the same life cycle and mode of transmission.

The lifecycle of Giardia is composed of two stages. The mature parasites, or trophozoites, live in the small intestine where they multiply and eventually become cysts. Cysts are the infective stage and are shed into the feces of the infected animal. They can survive for several weeks in the environment as cysts, and when they are ingested by an unsuspecting host, they turn into trophozoites and repeat the life cycle.

Giardia has to be ingested by your dog in order for him to get the parasite. Your dog can get Giardia by drinking water that has been contaminated by feces or by eating something that has been contaminated by feces, like grass. Since dogs love to put things in their mouths, this means that there are plenty of ways your dog can pick up the parasite in his environment, whether it is by chewing on a stick, eating poop, or drinking from a puddle.

Once the parasite is in your dog’s intestines, your dog can spread the parasite, even if he doesn’t show any signs of infection. This is worrisome, especially if you have more than one pet in your household. While transmission from dogs to cats and cats to dogs is unlikely, the transmission from dog to dog is certainly a cause for concern. If one of your pets is diagnosed with Giardia, talk to your vet about the precautions you need to take to protect your other pets.

Giardia in dogs does not always cause problems, but when it does it is highly unpleasant. Giardiasis is the term for the disease caused by the infection, and, as in humans, the most common symptom is diarrhea.

The parasite inhibits your dog’s ability to properly absorb nutrients, water, and electrolytes, which leads to diarrhea and weight loss. The diarrhea can be intermittent or continual, especially in puppies, and failure to diagnose and treat the disease can lead to severe weight loss and even death in extreme cases. The disease is particularly dangerous for puppies, senior dogs, and dogs with compromised immune systems.

The best way to determine whether your dog has Giardia or another condition is to call your vet. However, there are several symptoms of Giardia in dogs that dog owners should be aware of. These symptoms include:

If you notice that your dog is having diarrhea, call your vet. Your vet will probably conduct several diagnostic tests to determine if your dog has Giardia, and depending on the severity of the case she will discuss a treatment plan tailored to your dog’s needs.

An ounce of prevention is worth a pound of cure, the saying goes, and this is certainly true of Giardia. While we can’t always control every aspect of our dog’s environment, there are some things owners can do to prevent Giardia in dogs.

The most important thing is making sure your dog has access to fresh, clean water at all times in a bowl off the ground. This will reduce the chances of dogs lapping up water from infected puddles and is also vital for your dog’s general health. If you live in a place where Giardia is present in the tap water, purchase a filter that is proven to remove Giardia cysts from the water or boil your dog’s water. Boiling water will kill the cysts, but remember to let it cool before offering it to your dog!

The other important preventative action you can take is paying attention to general hygiene. Pick up after your dog as soon as possible. This will prevent the cysts from entering the environment and will also make your yard a healthier place for dogs and people.

You can also take care not to bring your dog to places where there are large amounts of dog feces, as this will limit the possibility of exposure. Boarding and training facilities that take the necessary steps to clean and disinfect runs and yards are less likely to have Giardia, along with a number of other unpleasant diseases.

Nobody wants to get Giardiasis. Luckily, the odds of humans being infected with Giardia from dogs is relatively low, although it can happen. Washing your hands after handling dog poop will reduce the already low risk even further and is also a good idea in general.

Giardia in humans is commonly transmitted through drinking water, not by our pets. Avoid drinking contaminated water, especially while traveling, and consider buying a water filter if your water source is known to contain the parasite. Giardia can also be present on food and in soil, so wash all produce before eating and wash your hands after working with dirt.