Catteries carry the highest published prevalence of any cat population that is not a hoarding seizure. This page is not about the drug — it is about the decisions a breeder actually makes: what to test before an introduction, what to do with a positive kitten, how a queen’s cycle changes the timing, and what you owe a buyer.
The risk factors named in the literature are housing density and age. That is a description of a cattery, and it is why pedigreed cats dominate the prevalence figures rather than any property of breeding itself:
| Population | Prevalence |
|---|---|
| Cats in large-scale hoarding operations, USA | ≈39% |
| Pedigreed cattery cats, USA | ≈31% |
| Long-term sanctuary cats with diarrhea | ≈26% |
| Long-term sanctuary cats with normal stool | ≈10% |
| Mixed pet-cat populations | ≈4–10% |
Read those as an order of magnitude: they come from different studies, assays and decades. Two consequences survive the imprecision. About a quarter of positive cats look completely normal, so a cattery cannot be assessed by looking at stool. And geography matters — the Australian cattery and shelter survey found prevalence far lower than the American figures at the time, so a negative result means something different depending on where the cat came from.
One more thing the cattery literature says plainly: coinfection is normal, not exceptional. Giardia turning up alongside this organism in a cattery is documented, and treating only one of them fails. Both papers are on the research index →
This is the moment the whole page exists for. A breeder buying in does the right thing and runs their own test before an introduction — and the test that comes back is not always the test they think it is.
There is no published trial that tells you which of these is right; the honest answer is that this is a decision made on welfare, money and your own risk tolerance, with your veterinarian.
Field experience, labeled as such: the breeders who come out of this with their reputation intact are the ones who told the buyer first, in writing, before the buyer found out from a laboratory invoice.
Ronidazole is considered contraindicated in pregnant or lactating queens, and kittens under about twelve weeks are usually dosed lower because their metabolism is immature. That single sentence reshapes a breeding plan: treatment has to fit around a cycle rather than the other way round, and a queen who is already pregnant or nursing is a different problem from one who is not.
There is also a welfare cost that rarely appears in a breeding forum. Confining a queen for weeks of treatment separates her from the company she is used to, and cats deteriorate in bare cages — the isolation has to be a room with a hiding place, vertical space, separated resources and daily human contact that is not only the moment of dosing. The welfare page sets that out properly →
Transmission is fecal–oral: shared trays, grooming after stepping in stool, and a queen shedding into the litter her kittens use. It is not inherited, and a positive kitten is not evidence of a genetic fault in a line.
Three sentences, in writing, with dates: what was tested and how, what the result was, and whether clearance was confirmed and how long after the last dose. If it was not confirmed, say that. Ambiguity here is what damages trust later, and it is also what puts the buyer’s other cats at risk.
The printable shelter checklist carries a fill-in disclosure paragraph that works unchanged for a cattery sale; print it and complete it at the handover.
Ideal, rarely affordable, and never a guarantee. If you cannot test everyone, the defensible middle ground is the same one shelters use: test every cat with diarrhea, test every cat arriving from a group with known positives, and treat the resident population as potentially positive until you have reason to think otherwise. Do not test only the cats with diarrhea and conclude the rest are clean — roughly a quarter of positive cats in dense populations have normal stool.
It is what some catteries do, and it is a management decision rather than a clinical one. It means the group stays a closed positive group: no negative cat enters, no cat from it is sold as clear, and every buyer is told. The risk is not the closed group; it is the assumption that a cat which stopped shedding is a cat which cannot shed again.
A negative is a point-in-time result on an assay of roughly 94% sensitivity, on a specified sample type, at a specified interval after exposure. It is a reasonable basis for a decision; it is not a certificate. If the stakes are a litter and a buyer’s household, test late enough and record what was tested and when, so the answer can be interpreted by someone else later.
That is a conversation with your veterinarian, not a website. Ronidazole is considered contraindicated in pregnant and lactating queens, kittens under twelve weeks are usually dosed lower, and the timing of treatment against a cycle is a clinical judgement with welfare consequences on both sides.
No. It is acquired fecal–orally, including from a shedding queen to the litter sharing her tray. A positive kitten is a housing and exposure question, not a genetic one, and treating it as a fault in the line is both unfair and inaccurate.
Separate the trays before you separate the cats: separate scoops, separate gloves, stool removed promptly, and enough trays that no cat queues at a soiled box. There is no cyst stage and the organism survives only days in moist stool, so routine disinfectants and frequent scooping do more than deep-cleaning once a week. The outbreak playbook has the full sequence →
