Summary of available information on prevalence :

• Studies in the UK, The Netherlands, Italy, Belgium, New Zealand and the USA have found that B. bronchiseptica is widespread in the feline population
• Seroprevalence ranges from 24% (Hoskins et al 1998) to 87% (McArdle et al 1994)
• B. bronchiseptica  can act as a primary pathogen causing URTD
• Studies have shown a clear association between B. bronchiseptica infection and URTD
• In US studies outbreaks of URTD have been shown to be more frequently associated with B. bronchiseptica than either FHV or FCV infection

Before 1991, there were only a few publications on the subject of isolation of B. bronchiseptica from either healthy cats or cats suffering from URTD (Fisk et al 1973, Snyder et al 1973). However, in the few diseased cats from which B. bronchiseptica was isolated, either FHV or FCV was also shown to be present, or no attempts had been made to isolate other pathogens. Therefore, it could not be determined whether isolation was an incidental finding in these cases.

In a later UK study of an outbreak of respiratory disease in a breeding cattery, 2 of 6 kittens that died were examined post mortem and samples of lung from these animals yielded positive cultures of B. bronchiseptica (Willoughby et al 1991). FCV was also isolated in the cattery and therefore it is uncertain whether B. bronchiseptica was acting as a primary or secondary pathogen in these cases.

In a further study of a closed breeding colony undergoing an outbreak of respiratory disease no FHV or FCV could be isolated and titres to Chlamydophila felis  were low (Elliot et al 1991). Cats showed symptoms very similar to those of canine kennel cough and B. bronchiseptica could be isolated from the cats with respiratory symptoms, but not from the healthy cats suggesting that B. bronchiseptica was the principle pathogen.

Since these early reports more extensive studies have been performed considering the prevalence of the bacterium and its association with disease. Such studies consider the seroprevalence of the disease and/ or the of the bacterium isolation rate.