Table 2.

Data extraction fields for categorisation.

Field	Category
Location (continent and country)	Descriptive
Length of study	Numeric (months)
Primary aim	Descriptive: prevalence, diagnostic evaluation, sample site evaluation, sequencing, etc.
Secondary aim	Descriptive: prevalence, diagnostic evaluation, sample site evaluation, sequencing, etc.
Pathogen	Binary indicator: FHV, FCV, Mycoplasma felis, Chlamydia felis, Bordetella bronchiseptica
Diagnostic method	Binary indicator: PCR, viral isolation, bacterial isolation, ELISA, other (descriptive)
Sample type	Binary indicator: oropharyngeal cytobrush, oropharyngeal swab, conjunctival swab, nasal swab, clinical signs, other (descriptive)
Sample size	Numeric
Population	Binary indicator: shelter, owned, other (descriptive), combination
Health status of sampled animals	Binary indicator: healthy, symptomatic, both
Risk factors	Descriptive (list)
Disease frequency	Numeric or descriptive based on reporting