Feline infectious Upper Respiratory Tract Disease (URTD) is a common problem in veterinary practice. In the past the problem has been mostly attributed to Feline Calici Virus (FCV), Feline Herpes Virus (FHV) and Chlamydophila felis (previously known as Chlamydia psittaci), although the latter is mainly a conjunctival pathogen. Despite the routine vaccination of cats against FCV, FHV and sometimes Chamydophila felis, feline infectious URTD continues to be a considerable problem. Furthermore, antibiotic treatment is often effective in the treatment of vaccinated cats suffering from URTD suggesting the involvement of a bacterium in the syndrome.

Recently, attention has shifted towards Bordetella bronchiseptica (B. bronchiseptica), a small, motile, aerobic Gram-negative bacillus which is involved in respiratory diseases in different animals including dogs where it causes tracheobronchitis (kennel cough, Appel and Binn 1987), and pigs where it contributes towards atrophic rhinitis (Magyar et al 1988). In 1991 the hypothesis was investigated that B. bronchiseptica could act as a primary respiratory pathogen in cats (Jacobs et al 1993).

In the field B. bronchiseptica has been isolated from cats with respiratory disease in breeding colonies known to be free of both FHV and FCV (Elliot et al 1991). It is, therefore, becoming apparent that this bacterium plays a significant role in some cases of feline infectious URTD. Epidemiological studies show that B. bronchiseptica is widespread in the feline population with disease being related to periods of stresssuch as that experienced in breeding and boarding catteries and during pregnancy and parturition.

Unlike most cases of feline infectious URTD a most alarming aspect of B. bronchiseptica infection in cats is the acute deaths which have been reported, particularly in young kittens when the disease progresses rapidly to bronchopneumonia.