Microsoft word - feline respiratory disease.doc

Feline Respiratory Disease
Background
Feline herpesvirus (FHV) is an important cause of ocular and upper respiratory tract (URT) disease
in cats. A typical α-herpesvirus, the virus establishes a latent infection in virtually all infected cats.
Latently infected cats are difficult to diagnose as they shed low levels of virus for a short time following
a stress event. Latently infected cats are an important source of infection for other cats.
Feline calicivirus (FCV) causes URT and oral disease in cats; oral ulceration is a typical feature. The
virus is shed for prolonged periods following infection (≥30 days in most cats) and a proportion of
infected cats become persistent shedders. Cats can be categorised as high, medium or low level
shedders; low shedders may require repeat swabbing to be detected. FCV is not a primary
conjunctival pathogen.
Chlamydophila felis is typically associated with conjunctivitis, particularly in cats <1 year of age.
Additional URT signs can occur but are not common.

Bordetella bronchiseptica is a primary pathogen in cats and is associated with an array of clinical
signs ranging from URT signs to bronchopneumonia.
Diagnosis
Virus Isolation (VI) is the gold standard for FHV and FCV diagnosis. This method detects viable
virus. Samples are inoculated onto tissue culture cells which are monitored over 4 days for the
development of characteristic cytopathic effects (CPE). FCV outgrows FHV in tissue culture, which
means it is rarely possible to detect both FHV and FCV in a single sample. Therefore, if a sample is
FCV positive, this does not necessarily mean it is FHV negative. In our laboratory, over 25% of FCV-
positive samples are also FHV-positive. PCR is the only method to detect FHV in FCV-positive
samples.

PCR is used in our laboratory to detect FHV and C. felis. PCR is more sensitive than VI for FHV
diagnosis: our FHV PCR test detects nearly three times as many FHV-positive samples as VI. PCR
detects viral DNA and not necessarily viable virus.

Bacterial Culture: nasal swabs or tracheal washes submitted in bacterial transport medium are
cultured on selective medium for Bordetella bronchiseptica isolation.
Treatment
FHV: Supportive therapy. L-lysine orally can reduce shedding rate in latently infected cats. Feline
interferon (IFN) -ω is effective in vitro but no controlled in vivo studies have been published.
FCV: Supportive therapy. Feline IFN-ω has been shown to be effective in vitro but no controlled
clinical studies that demonstrate in vivo efficacy are available.
Chlamydophila felis: Doxycycline has been shown to be effective against C. felis and may require a
prolonged 4 week course to eliminate infection. All cats in the household should be treated. Care
should be taken with the use of tetracyclines in pregnant cats and young kittens. Amoxycillin-
clavulanate treatment for 4 weeks is also effective.

Bordetella bronchiseptica: Tetracyclines, particularly doxycycline, are the preferred treatment for
Bordetellosis (but should not be used in pregnant cats or young kittens).
Veterinary Diagnostic Services
School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow Bearsden Road, Glasgow G61 1QH, United Kingdom Tel: +44 (0)141 330 5777 Fax: +44 (0)141 330 5748 The University of Glasgow, charity number SC004401

Source: http://www.gla.ac.uk/media/media_198537_en.pdf