Table 1.

Variables assessed as potential risk factors for oral carriage of feline herpesvirus, feline calicivirus and Chlamydia felis

Variable	Description	Categories
Breed (Q1)	Breed of the cat	Crossbred (comprising domestic shorthair, domestic longhair and other crossbreeds)
		Purebred (as given by owner; not a “domestic” breed or cross‐breed)
Sex (Q1)	Sex of the cat	Male
		Female
Neuter status (Q3)	Whether the cat was neutered between two‐18 months	Entire
		Neutered
Outdoor access (Q2) (Q3) (Q4)	What indoor and outdoor access the cat was given	Q2
		Indoor only
	For the purpose of univariable analysis, any cats that are not kept exclusively indoors are categorised as having outdoor access
		Indoor and outdoor access
		Outdoor only
		Q3 and Q4 a
		Inside only – cat is not allowed outside
		Inside – cat goes out into enclosed “run” or on a lead
		Inside and outside
		Outside only – cat is not allowed in the house
Single or multi‐cat household (Q1) (Q3) (Q4)	Derived from combining the response in Q1, Q3 and Q4	Consistently a single cat household
		Multi‐cat household at any time point
Vaccination (Q2)	Whether the cat has received first vaccination course	Vaccinated
		Unvaccinated
URTD signs observed by owners (Q2) (Q3) (Q4)	Derived from combining the response in Q2, Q3 and Q4	Attacks of wheezing with whistling on the chest
		Attacks of breathlessness
		Sneezing
		Cough
		Runny nose
		Mouth ulcers
		Drooling
		Sore/ red/ runny eyes
Diagnosis of “cat flu” (Q2) (Q3) (Q4)	Derived from combining the response in Q2, Q3 and Q4	Yes – diagnosed by vet
		Yes – but was not seen by a vet
	Whether the cat had been diagnosed with “cat flu” at any time point (“Has your cat had cat flu since you have owned him/her?”)	No

^a Additional rows included in “Categories” for outdoor access due to changes in the terminology between questionnaires