Signs
The presenting signs do overlap between infections with the different organisms,
but sneezing, a high body temperature and general
dullness are common to all of them. Some signs are more typical of specific
infectious organisms than others. Recurrent and persistent conjunctivitis - with
inflammation of the eye and a purulent bilateral discharge is typical of
Chlamydia infection, whereas calicivirus frequently causes sever ulceration in
the mouth. Rhinotracheitis virus causes corneal ulcers and is most likely to
affect the lower respiratory tract, which can lead to secondary pneumonia, as
well as systemic effects such as abortion in infected queens.
If untreated mild cases of cat flu can progress to pneumonia due to
secondary infections.
Diagnosis
The infectious agents that cause cat flu can be identified from a variety of
tests including isolation from swabs, and from blood tests (measuring
antibodies) in some cases. Unfortunately interpretation of the results can be
misleading. For example, some of the viruses that can cause the signs of cat flu
may be found in samples taken from healthy, unaffected animals. This means that
a cat's immune system probably has to be compromised for it to develop the
disease.
In prolonged cases or cases unresponsive to conventional treatment it is wise
to screen for the presence of feline leukaemia virus (FeLV) or feline
immunodeficiency virus (FIV) as these may compromise immune response making
recovery difficult.
Treatment
There is no specific treatment for the viruses that cause cat flu but
symptomatic treatment and care is needed. The exception to this rule is for
corneal ulcers caused by feline rhinotracheitis virus, as these can be treated
with the antiviral agent trifluoridine - which is applied 8-10 daily to the eye.
Providing an infected cat is able to mount a normal immune response to the
infection, viral cat flu is a self-limiting disease and most cats recover in 2-3
weeks. A small number of cats become chronic carriers of the infection-
particularly if they have concurrent feline leukaemia virus (FeLV) or feline
immunodeficiency virus (FIV) infection.
Bacterial infections are treated with antibiotics - usually ampicillin,
amoxycillin, tetracyclines or potentiated sulphonamides.
Chlamydia infection is treated with tetracyclines - usually given by
injection for a week, as local administration into the eye is less effective.
In all cases the opening to the nose should be kept clean by wiping away
collected debris and discharges. Sometimes the use of a nebuliser or
decongestants (e.g. pseudoephidrine) is recommended in severe cases.