Your kitten comes home happy and healthy. You instantly start to fall in love.
A week later, they sneeze…or maybe they develop diarrhea.
You visit your veterinarian, a PCR or fecal panel is run, and suddenly you have the name of a virus, bacterium, or parasite staring back at you from a laboratory report.
It is very easy to make the next leap:
My new kitten is sick, so they must have come home sick.
Symptoms After Rehoming ≠ Sick When Placed
The timing makes that conclusion feel obvious. New kitten + illness = sold a sick kitten.
But the problem is, it just isn't that simple…
It should be expected that when you bring your kitten home, they are healthy. After all, you have made a significant investment and placed your trust in a breeder to provide you with a healthy new member of your family.
No responsible breeder should knowingly send home a sick kitten. Period.
Here’s the thing, though: a kitten can leave their breeder perfectly healthy—eating normally, playing, producing normal stool, and showing absolutely no signs of active illness—and develop a sniffle or digestive upset after arriving in their new home.
Moving is a big deal for a kitten. New sounds, new smells, new water, new routines—and suddenly their littermates and everything familiar are gone.
That stress causes real physiological changes. A natural rise in cortisol can temporarily affect immune function and disrupt the normal balance of the gut microbiome.
That temporary change can give any lurking viruses, bacteria, or other organisms an opportunity to take hold or become more active.
So my kitten was sick when it went home?
Not necessarily.
Kittens can carry organisms without being sick. Some are harmless, some are normal inhabitants of the body, and some have the potential to cause illness if circumstances change.
Now you're probably thinking: Wait—how can a kitten carry something that could make them sick and still be healthy? Doesn't having it automatically make them sick?
No.
A kitten's immune system can keep an organism in check while the kitten eats, plays, grows, and behaves completely normally.
What we're watching for is clinical illness.
What do you mean by clinical illness?
Clinical illness simply means the kitten is actually showing signs of being sick—things like sneezing, diarrhea, loss of appetite, lethargy, fever, or abnormal discharge.
A kitten can have an organism present without having clinical illness. The presence of the organism alone doesn't mean the kitten is sick.
Okay…so where did the organism come from?
Kittens don't live in sterile environments. Neither do we.
Think about your own home. Maybe you leave your shoes at the door, but do you immediately strip down and shower every time you come inside? Do you disinfect your phone, purse, packages, groceries, and everything else that crosses the threshold?
Probably not.
And that's okay.
Healthy ≠ Sterile
There is a difference between a clean, well-managed environment and a sterile one.
To truly keep a cattery sterile, we would need something resembling a laboratory clean room. We would have to decontaminate ourselves every time we entered, sterilize everything coming in—including food and water—and somehow prevent the kittens themselves from exposing one another.
That's neither realistic nor how we want kittens to be raised.
We clean. We disinfect. We practice appropriate biosecurity and quarantine. But our kittens also live in our home, interact with people and other kittens, play, explore, and experience normal life.
A home is an ecosystem, not a clean room.
So…did the organism come from the breeder?
Maybe.
Your kitten has lived with their mother, littermates, other kittens, and humans. They have eaten food, drunk water, visited the veterinarian, touched surfaces, and lived in the real world.
Could they have encountered an organism while living with their breeder?
Of course.
That's part of being raised in a clean, well-managed home—not a laboratory.
Even if we did raise your kitten in a sterile clean room—is that how you are going to raise them?
Of course not.
They are going to be a beloved member of your family. They are going to live in your home, interact with you, explore, play, cuddle, and experience everyday life.
The moment they leave our cattery, they are introduced to the unique biological environment of your home.
Your resident cats and dogs have their own biological histories. So do the humans in your household. Microorganisms come inside on our shoes, clothing, hands, and belongings. Some organisms can even pass between species.
Your home has its own microbiological ecosystem—just like ours does.
Okay, but why not test every kitten before they go home?
If healthy kittens can carry organisms without anyone knowing, why not simply test them all before they leave?
Then, if something comes back positive, we could treat it before the stress of transitioning to a new home gives it an opportunity to cause illness, right?
The problem is that a positive test doesn't necessarily mean there is anything to treat.
A PCR test, or polymerase chain reaction, looks for genetic material from specific organisms in a sample.
If a PCR comes back positive, it means genetic material from that organism was detected.
It does not necessarily mean that organism is causing disease.
Okay…but if the organism is there, why not treat it anyway?
Why not “kill” it before it ever has the opportunity to make the kitten sick?
Because not every organism detected in a healthy kitten needs to be eliminated.
Some microorganisms are normal inhabitants of a kitten's body. Others may be carried without causing any clinical illness at all. Treating simply because something was detected can mean medicating a perfectly healthy kitten for something that isn't actually causing a problem.
And when that treatment involves antibiotics, there is another concern: antibiotic resistance.
Antibiotics kill or suppress susceptible bacteria, while resistant bacteria are more likely to survive. Using antibiotics when they aren't needed gives resistant bacteria an advantage.
But if we treat it now, won't that prevent the kitten from needing antibiotics later?
Not necessarily.
Treating an organism today doesn't prevent your kitten from encountering it—or another organism—again in the future.
They are going to continue encountering microorganisms throughout their life.
So unnecessarily treating a healthy kitten now doesn't guarantee they won't need antibiotics later.
And when they do genuinely need them, we want those antibiotics to work.
The goal isn't to eliminate every organism a healthy kitten might carry. The goal is to treat disease appropriately when it occurs.
So how do we know when a kitten actually needs treatment?
We evaluate the whole kitten.
A test result is only one piece of information. We also look at the kitten in front of us.
Are they eating? Playing? Growing? Are they hydrated? Do they have a fever? What symptoms are they showing? How severe are they? Are they getting better or worse?
Imagine two kittens test positive for the exact same organism.
One is bright, playful, eating normally, and showing absolutely no symptoms.
The other is lethargic, running a fever, refusing food, and showing significant symptoms.
The laboratory result may be identical. The kittens aren't.
But couldn't a breeder use all of this to excuse genuinely unhealthy kittens?
Absolutely. And they shouldn't.
Understanding that healthy kittens can carry organisms is not an excuse for poor husbandry or poor health.
One kitten developing mild symptoms after a stressful transition is one thing. But if multiple littermates develop the same problems, the same issues appear across different litters, or kittens routinely struggle to recover from ordinary infections, that is a pattern.
We look at sanitation and biosecurity. We review our protocols. We investigate when something doesn't seem right.
Sometimes, what we learn changes our breeding decisions.
If a particular pairing consistently produces kittens that seem unusually susceptible to illness or have difficulty fighting off ordinary infections, we may choose not to repeat that mating.
A responsible breeder should never knowingly produce sickly kittens, and they most certainly should never send an actively sick kitten home.
Unfortunately, not every breeder operates responsibly, and information like this should never be used to excuse poor husbandry, recurring illness, or knowingly placing sick kittens.
Do your research, choose a responsible breeder you trust, and keep that relationship open after your kitten comes home.
Remember: accepting that pathogens are part of life does not mean accepting poor health.
The Whole Picture
Just because your new kitten gets sick shortly after coming home does not automatically mean you were sold a sick kitten.
Healthy kittens can carry organisms. Stress can cause them to rear their ugly heads. Exposure is part of living in the real world. And a positive test doesn't necessarily mean a kitten is clinically sick or needs treatment.
That is why we evaluate the whole kitten.
We watch. We investigate when appropriate. We treat when treatment is warranted. And as breeders, we pay attention to patterns that may tell us something needs to change.
Our goal isn't to eliminate biology. It's to understand it well enough to make thoughtful decisions for the kittens in our care.