Giardia in dogs

Written by Dr Andrew Miller MRCVSDr Andrew Miller MRCVS is an expert veterinary working in the field for over 10 years after graduating from Bristol University. Andy fact checks and writes for Pure Pet Food while also working as a full time veterinarian. Pure Pet FoodPure Pet Food are the experts in healthy dog food and healthy dogs featured in media outlets such as BBC, Good Housekeeping and The Telegraph. Working with high profile veterinary professionals and nutritionists, Pure Pet Food are changing dog food for the better. - Our editorial process

Giardia is a tiny, pesky parasite that can cause the disease giardiasis. Just as common in dogs as it is in humans, the parasite can infect anyone, but it commonly occurs when people are travelling to different countries.

Humans catch giardia by drinking water that is contaminated with the parasite. When travelling to places they aren’t familiar with, people can often unknowingly drink water that has been infected with giardia and become unwell.

Giardia is the major cause of what humans refer to as ‘traveller’s diarrhoea’. This unwelcome symptom is the main one that humans share with dogs who have caught giardiasis.

What is giardia in dogs?

A very small parasite that lives in the small intestine, giardia is infectious and can cause your dog to feel very unwell.

It lives in a continuous life cycle that has two forms, starting with the trophozoite. This is the older form of the parasite, and it attaches itself to the lining of the intestine, eventually multiplying and some then turning into cysts.

These cysts are the infectious part of giardia, and they arise in the faecal matter of the infected dog. The life cycle continues to be repeated when the cysts that appear in a dog’s poo are somehow ingested by another dog. This is where they turn back into trophozoites.

If your dog starts to get symptoms, the main one being diarrhoea, they’ll have developed the disease giardiasis.

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Although lots of parasites seem to perish in the colder months, giardia actually survives and even thrives in cooler, moist conditions.

What causes giardiasis in dogs?

The parasite spreads through poo - a dog will catch it when they come into contact with the contaminated faeces particles.

Most dogs like to explore, usually by getting their mouth around anything in sight. For instance, poograsssticks, puddles and whatever else you could possibly think of. The parasite could be lurking on any of these items, making it very easy for your dog to ingest infected cysts.

Environments that are heavily populated with dif-fur-ent pooches are where giardiasis is extremely prevalent, such as kennels and animal shelters.

What are the signs and symptoms that my dog has giardiasis?

Signs and symptoms of giardiasis include:

Giardia infects many of our pups, but a lot of the time, we wouldn’t even know. Often, dogs who are infected with giardia won’t develop the disease of giardiasis and never experience any of the common symptoms. Despite this, even the asymptomatic dogs can still spread the parasite to other pooches.

The best thing to do is contact your vet if your furry friend is suffering from any of these symptoms. Even though it’s usually not severe, it causes discomfort for your pooch and it’s definitely not the most pleasant for the both of you!

Are some dogs more likely to suffer the symptoms of giardia infection?

In healthy, adult dogs, giardia usually doesn’t have any impact. Even if a vet picks up on infectious cysts in a healthy dog’s stool, it will likely be considered as relatively unimportant.

However, the parasite limits a dog’s ability to soak up necessary nutrients, so it can cause serious issues in puppies, senior pooches and dogs already suffering from health issues. As their immune system is either underdeveloped or compromised, it means they struggle to fight off the impact of the parasite.

How is giardiasis in dogs diagnosed and treated?

Diarrhoea is the most common and obvious sign of giardiasis, but diarrhoea can also be a symptom of various other illnesses. Therefore, the vet will require a stool sample from your pup to complete a full diagnosis.

Preventing diarrhoea from spreading and infecting other dogs is essential, so upon noticing diarrhoea, get your dog to the vet quickly. Diarrhoea can also cause your dog to be severely dehydrated, so getting treatment is necessary.

Once diagnosed, your vet will prescribe your pooch with a course of antibiotics, but it’s likely that more than one course will be required to completely eliminate the disease.

Although it’s rare, some cases of giardiasis can be relatively serious and demand more intense treatment, for instance, a drip to provide more fluids.

Dogs infected with giardia will more than likely make a complete recovery, it’s extremely unusual for your pooch to experience any further issues after treatment.

Can humans catch giardia from dogs?

As we know, giardia is a parasite that infects both humans and animals. Giardiasis is technically classed as ‘zoonotic’, which essentially refers to a disease that can spread from animal to human.

Despite this, the strain of giardia that infects our pets isn’t actually that common in humans, meaning that it’s quite rare to catch the disease from your dog. When humans catch giardia, it’s more likely to happen from drinking contaminated water, especially when travelling to new countries. However, your pooch passing it on to you isn’t entirely impossible.

Even though it’s pretty rare for you to catch it, you should still be cautious for both yourself and other dogs. Washing your hands immediately after cleaning up dog poo is very im-paw-tent so you don’t catch the infection.

Also, if you have several furry friends and you think one of them is infected with giardia, try keeping them separate until the disease has passed. It’s very easily transmitted from dog to dog.

Can I prevent my dog from being infected with giardia?

Fully preventing your pup from becoming infected with giardia is impossible, as they can be exposed to the parasite almost anywhere, and we can’t have total control of where our dogs go, what they try to eat or what they try to drink. However, there are certainly ways to reduce the chances of infection, for instance:

  • Picking up dog poo straight away in the garden so your dog doesn’t eat it

  • This can be tricky, but teaching your dog the ‘leave it’ command so you can hopefully stop them from eating faeces from other animals on a dog walk

  • Ensuring that your dog has plenty of clean water to drink from at all times, hopefully this will stop your dog wanting to quench their thirst in a filthy puddle

  • Giardia can be found anywhere, but there are some locations where it is definitely present. Buying a water filter known to remove giardia is highly advisable if you live in one of these areas. Boiling water removes giardia cysts, so this is also an option.

  • If you think your dog has been infected, it’s essential to keeping on top of grooming, as faeces can often get stuck under their tail or in long fur. Reinfection happens frequently, so make sure all faeces are out of your dog’s fur.

If your dog is already infected with giardia, it’s best to try and avoid walking them in somewhere highly pooch populated, to prevent anymore dogs getting poorly.

Overall, giardia is not something to be overly concerned about. Healthy, adult dogs are at little risk of getting severely poorly, it’s just dogs with a weaker immune system that may struggle with the parasite. However, with the right treatment and care your pooch will be back on track in no time.