Giardia in Cats: Symptoms, Causes and the Rise in Cases in North West London
- 21 minutes ago
- 13 min read
Over the past few weeks at Roundwood Vets, we’ve noticed something a little unusual that we wanted to share with our local cat families.
We are seeing more cases of Giardia in cats than we would normally expect, and what has particularly caught our attention is that several of the cats affected are indoor cats.
Some have had relatively mild tummy troubles, but unfortunately, we have also seen cats become quite poorly. A few have experienced significant diarrhoea, vomiting, reduced appetite and dehydration and have needed to stay with us for intravenous fluids and supportive care.
We don’t want this to worry everyone with an indoor cat. There are lots of reasons why cats develop diarrhoea or vomiting, and Giardia is only one possibility.
However, because the number of Giardia-positive cats we are currently seeing feels unusual for us, we thought it was important to let our North West London cat-owning community know what we are seeing, explain a little more about Giardia, and share the signs we would like you to look out for.
And, of course, answer the question we have been hearing quite a lot recently:
“How has my cat caught Giardia when they don’t even go outside?”
Contents
What is Giardia in cats?
Giardia is a microscopic parasite that lives in the intestinal tract. It can infect cats, dogs, people and other animals.
It isn’t a worm, and you won’t be able to see Giardia in your cat’s poo. Instead, it is a tiny single-celled organism called a protozoan.
An infected animal can pass microscopic Giardia cysts in their faeces. These cysts can contaminate the environment and potentially be swallowed by another susceptible animal.
This is known as faecal-oral transmission.
That may sound as though your cat would need to come into direct contact with another animal’s poo, but that isn’t necessarily the case. Giardia cysts are microscopic, so contamination can be completely invisible to us.
Some cats can carry Giardia without appearing unwell at all. In others, it can cause gastrointestinal illness, known as giardiosis, with diarrhoea being the most commonly recognised symptom.
Why are we talking about Giardia now?
Quite simply, because we are seeing more Giardia-positive cats at Roundwood Vets than we would normally expect.
We want to be clear that we are not declaring a confirmed Giardia outbreak across North West London. This is an observation based on the cats we are currently seeing in our own practice.
But when we start to notice an unusual pattern among our patients, we pay attention.
What has particularly stood out to us is that:
We have seen an unusual number of Giardia-positive cats in a relatively short period
Several of the affected cats are indoor cats
Some have had significant gastrointestinal symptoms
Some have experienced vomiting and reduced appetite alongside diarrhoea
A few have become dehydrated and poorly enough to require hospitalisation, intravenous fluids and supportive care
Thankfully, with appropriate veterinary treatment and supportive care, affected cats can recover very well.
At the moment, we don’t know why we are seeing more cases, and there may not be one straightforward explanation.
We simply feel it is worth making our clients aware of what we are noticing.
Can indoor cats get Giardia?
Yes, they can.
And this has probably been the biggest surprise for some of the owners we have spoken to recently.
It is completely understandable to think:
“My cat never goes outside. How could they possibly have picked up a parasite?”
Unfortunately, being an indoor cat doesn’t mean living in a completely sealed environment.
Giardia spreads when microscopic cysts originating from infected faeces are swallowed. These cysts may be present in contaminated water, food or the environment.
Because we cannot see them, it isn’t always possible to work out exactly where an individual cat has been exposed.
How does Giardia spread to cats?
Possible routes of exposure can include:
Another infected cat in the household
Shared litter trays
A newly introduced cat or kitten
Contaminated paws or fur followed by grooming
Contaminated food or drinking water
Contaminated soil
Contaminated objects or surfaces
Previous stays in catteries, rescue centres or other multi-cat environments
Microscopic contamination inadvertently brought into the home, for example on the soles of shoes
Another complication is that not every infected cat develops symptoms. A cat could potentially carry Giardia without anyone realising.
So, while keeping a cat indoors can reduce exposure to many parasites and infectious diseases, it does not mean that the risk is necessarily zero.
Can Giardia be brought indoors on our shoes?
Potentially, yes.
This is one possible way an indoor cat could encounter environmental contamination without ever setting a paw outside.
If we walk through soil or another surface contaminated with microscopic traces of infected faecal material, Giardia cysts could potentially be carried mechanically on the soles of our shoes and brought into the home.
That doesn’t mean that every pair of outdoor shoes poses a Giardia risk, and we certainly don’t want everyone worrying about disinfecting their shoes every time they walk through the front door.
It simply helps us understand that an indoor cat is not completely separated from the outside environment.
Think about a cat who likes to investigate your shoes when you come home, or who walks across the hallway floor before later grooming their paws. Cats are wonderfully thorough groomers, so microscopic contamination that we cannot see can potentially find its way from their paws to their mouths.
We cannot say that shoes are responsible for the cases we are currently seeing. They are simply one example of how microscopic environmental contamination could potentially make its way indoors.
As a sensible precaution, if you know you have walked through animal faeces or a particularly dirty or contaminated area, cleaning your footwear and leaving outdoor shoes near the entrance rather than walking through the house in them is reasonable.
There is no need to become obsessive about it. Normal, sensible hygiene is enough.
Can dogs get Giardia too?
Yes, dogs can get Giardia too, and we know that this may be a concern if you have both cats and dogs at home.
The reassuring thing is that the types of Giardia most commonly found in dogs and cats are usually different. Dogs most commonly carry dog-adapted types, while cats most commonly carry a cat-adapted type. These dog-specific strains are not known to infect cats, and the cat-specific strain is not known to infect dogs.
So, if your dog has Giardia, it does not automatically mean your cat is going to catch it, or vice versa.
There is a little more complexity, however. Some types of Giardia can occasionally be found in more than one species, so we cannot say that cross-species infection is completely impossible.
There is also the shared environment to think about. Giardia cysts are passed in faeces and can contaminate the surrounding environment, including floors, paws, bedding, bowls and other surfaces. If you have several pets at home, good hygiene is therefore particularly important.
If one of your cats or dogs tests positive for Giardia, please let us know about the other pets in your household, especially if any of them have developed diarrhoea, vomiting or other tummy troubles.
It does not mean that every pet automatically needs treatment or testing. We can look at your individual household and advise you on the most appropriate next steps.
Could flies or other insects carry Giardia?
This is an interesting question, particularly when we are seeing Giardia in indoor cats without an obvious source of infection.
There is evidence that flies and some other insects can mechanically carry Giardia cysts after coming into contact with contaminated material.
The important word here is “mechanically”.
The insect doesn’t necessarily become infected with Giardia. Instead, microscopic contamination may potentially be carried on its body from one place to another.
In theory, an insect could therefore come into contact with contaminated material and later land on food, water or another surface.
However, we need to be careful about how we interpret this.
Insects are not considered one of the main established routes of Giardia transmission to household cats, and we certainly cannot say that insects are responsible for the cases we are seeing at Roundwood Vets.
It is an interesting possibility rather than an explanation for our current cases.
What it does demonstrate is how difficult it can sometimes be to identify exactly how microscopic contamination has entered an indoor environment.
What are the symptoms of Giardia in cats?
Not every cat with Giardia will become poorly.
Some cats may carry the parasite without showing any obvious symptoms at all.
When Giardia does cause illness, diarrhoea is the most common sign.
You may notice:
Soft or poorly formed poo
Watery diarrhoea
Diarrhoea that improves and then returns
Mucus in the poo
More frequent trips to the litter tray
A messy bottom or hind legs
Reduced appetite
Weight loss
Vomiting in some cats
Your cat being quieter or more lethargic than usual
Dehydration if gastrointestinal symptoms are significant
One of the things owners sometimes tell us is:
“The diarrhoea seemed to be getting better, and then suddenly it came back again.”
That sort of history can be really useful when we are trying to work out what might be happening.
Can Giardia cause vomiting and nausea in cats?
It can, although diarrhoea is the symptom we most commonly associate with Giardia.
Vomiting may occur in some affected cats, but it isn’t necessarily present in every case.
Nausea can be a little more difficult for owners to recognise because our cats can’t simply tell us that they feel sick.
Instead, you might notice your cat:
Walking up to their food and then turning away
Eating much less than usual
Licking their lips
Swallowing repeatedly
Drooling
Sniffing their food but seeming reluctant to eat
Hiding or appearing unsettled
These signs aren’t specific to Giardia. Many gastrointestinal conditions can make a cat feel nauseous, which is why it is important not to assume that Giardia is responsible without appropriate veterinary assessment.
With some of the cases we have seen recently, vomiting, poor appetite and lethargy have occurred alongside diarrhoea, so we feel these are useful signs for our clients to be aware of.
When should I worry about diarrhoea or vomiting?
This is one of the most important things we would like our clients to take away from this article.
A cat who has one slightly soft poo but is bright, happy and eating normally is very different from a cat who has frequent watery diarrhoea, is vomiting, has stopped eating and is becoming increasingly quiet.
Some of the Giardia-positive cats we have seen recently have lost enough fluid through their gastrointestinal illness to become significantly dehydrated.
A few have needed to stay with us at Roundwood Vets for intravenous fluids and supportive care.
So please look at your cat as well as the contents of the litter tray.
Ask yourself:
Are they eating normally?
Are they drinking?
Are they coming to greet you?
Are they interested in what is going on around them?
Are they hiding more than usual?
Do they simply seem “not quite right”?
You know your own cat incredibly well, and sometimes that feeling that something isn’t right is important.
Please contact us promptly if your cat has significant diarrhoea or vomiting and is also:
Not eating or eating significantly less
Very quiet or lethargic
Weak
Hiding much more than usual
Losing weight
Showing signs of discomfort
Vomiting repeatedly
Passing very frequent or watery diarrhoea
Showing any other signs that concern you
We would also want to hear from you sooner if your cat is a kitten, elderly, or has another health condition.
How is Giardia diagnosed in cats?
If your cat has persistent or recurrent diarrhoea, we may recommend testing a faecal sample.
At Roundwood Vets, we can carry out an in-house test for Giardia, which means we can often get useful information quickly without having to send the sample away.
Depending on your cat’s symptoms and history, we may also recommend sending a faecal sample to an external veterinary laboratory for more comprehensive testing. This can be particularly helpful when we want to look for Giardia alongside other possible causes of gastrointestinal symptoms.
Sometimes we may ask you to collect samples over more than one day. Giardia is not necessarily shed in every stool, so testing more than one sample can sometimes help us get a clearer picture.
And please don’t feel remotely embarrassed about arriving at reception carrying a poo sample!
We deal with them every day, and they can give us an enormous amount of useful information.
It is important to remember that we cannot diagnose Giardia simply by looking at the appearance of your cat’s poo.
Diarrhoea, vomiting and reduced appetite can have many different causes, including:
Dietary changes
Food sensitivities
Other parasites
Bacterial or viral infections
Inflammatory gastrointestinal conditions
Stress
Other underlying illnesses
We will look at your cat’s symptoms, their history and examination findings and then advise you on the most appropriate testing for them.
Sometimes our in-house Giardia test may be a sensible first step. In other cases, we may recommend sending a faecal sample to the external laboratory for a more comprehensive investigation.
As always, it is about choosing the right test for the individual cat in front of us.
Does a positive Giardia test always mean Giardia is making my cat ill?
No, and this is an important distinction.
Some cats can test positive for Giardia while appearing perfectly healthy.
A positive result therefore needs to be interpreted alongside your cat’s symptoms, history, examination findings and individual circumstances.
A bright, happy cat with normal stools is a very different patient from a cat with profuse diarrhoea, vomiting, reduced appetite and dehydration.
This is why we always look at the whole cat rather than treating a laboratory result in isolation.
How is Giardia treated in cats?
Treatment will depend on the individual cat, their symptoms and how unwell they are.
Cats with symptomatic Giardia may require veterinary-prescribed anti-parasitic medication, alongside supportive care where needed.
If your cat has become dehydrated, is vomiting frequently or is struggling to eat and drink, they may need additional treatment.
As we have seen with some of our recent patients, this can occasionally mean staying with us so that we can give intravenous fluids, manage their symptoms and monitor them carefully while they recover.
Please don’t try to treat suspected Giardia yourself or use medication left over from another pet.
If your cat has diarrhoea or vomiting, we first need to understand what is causing it so that we can recommend the most appropriate treatment.
Why can Giardia come back?
One of the frustrating things about Giardia is that symptoms can sometimes return after treatment.
There can be several reasons for this, and one possibility is reinfection.
Giardia cysts passed in faeces can contaminate the environment. If microscopic cysts remain around the litter tray, on bedding, fur or other contaminated areas, a cat may potentially swallow them again.
This is why dealing with Giardia can involve two parts:
Treating the cat and reducing contamination within their environment.
How can I reduce the risk of Giardia reinfection at home?
If your cat is diagnosed with symptomatic Giardia, we will talk you through the hygiene measures appropriate for your particular household.
These may include:
Removing poo from litter trays promptly
Cleaning litter trays thoroughly and regularly
Washing food and water bowls
Cleaning contaminated surfaces
Washing soiled bedding at 60°C or above where the material allows
Allowing cleaned areas to dry thoroughly
Keeping the fur around your cat’s bottom clean if it becomes soiled
Washing your hands carefully after cleaning litter trays or handling diarrhoea
If you have several cats at home, please don’t automatically assume that every cat needs treatment.
Give us a call and we can advise you based on your individual household and the symptoms, if any, that your other cats are showing.
Can people catch Giardia from cats?
This is understandably something owners worry about.
The reassuring news is that the risk of Giardia transmission from cats and dogs to people is generally considered to be low because different genetic types of Giardia tend to be associated with different hosts.
Nevertheless, good hygiene is always sensible.
Wash your hands thoroughly after:
Cleaning litter trays
Handling diarrhoea
Cleaning soiled bedding
Cleaning your cat’s bottom
Handling potentially contaminated surfaces
If anyone in your household develops gastrointestinal symptoms and is concerned about possible Giardia exposure, they should speak to their GP for appropriate medical advice.
Should my healthy indoor cat be tested for Giardia?
If your cat is bright, happy, eating normally and producing their usual stools, please don’t panic because you have read that we are seeing more Giardia cases.
We are sharing this information for awareness, not alarm.
We are not suggesting that every indoor cat in North West London needs to be tested for Giardia.
What we would like you to do is simply be a little more aware of changes in your cat’s litter tray, appetite and behaviour.
If diarrhoea develops and doesn’t settle, keeps returning, or is accompanied by vomiting, reduced appetite or your cat becoming unwell, that is the time to give us a call.
Keep an eye on the litter tray, but also keep an eye on your cat
It may not be the most glamorous part of sharing your home with a cat, but the litter tray can tell us an awful lot.
If their poo suddenly changes, make a mental note of it.
How often are they going?
Is it very watery?
Is there mucus?
Does it improve and then return?
Are they vomiting as well?
Are they still eating?
And if you need to take a photograph to show us, please do. Veterinary camera rolls contain far more photographs of poo than most people would probably imagine!
Most importantly, keep an eye on the cat attached to the poo.
A change in their appetite, behaviour or energy levels can be just as useful to us as what you are seeing in their litter tray.
When should I contact Roundwood Vets?
Please get in touch if your cat has persistent, recurrent or significant diarrhoea, particularly if they are also vomiting, eating less, losing weight or behaving differently.
If your cat seems very unwell, weak or unusually sleepy, is repeatedly vomiting, has stopped eating or drinking, or you are worried they may be becoming dehydrated, please contact us promptly.
And please don’t dismiss gastrointestinal symptoms simply because your cat lives indoors.
Some of the Giardia-positive cats we have seen recently have been indoor cats, and a few have become poorly enough to need intravenous fluids and hospital care.
A little message from us
We know that hearing we are seeing more Giardia cases locally might sound worrying, especially if you have an indoor cat and have always thought parasites were something you didn’t really need to think about.
Please don’t panic.
We don’t currently know why we are seeing more cases, and we are not suggesting that there is a confirmed outbreak across North West London.
We simply wanted to share what we are noticing here at Roundwood Vets because the number of Giardia-positive cats has been unusual for us, several have been indoor cats, and some have been more poorly than we might expect from a straightforward tummy upset.
For now, our advice is very simple.
Keep an eye on your cat, keep an occasional eye on the litter tray, and if something doesn’t seem right, please give us a call.
If you find yourself sitting at home wondering, “Do I need to worry about this?”, we would always rather you speak to us. We can listen to what has been happening and help you decide whether your cat needs to come in and see us.
Take care of yourselves and your lovely cats.
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