Answer: Infectious diseases are, by definition, specific diseases caused by microorganisms (bacteria, viruses, fungi and protozoa)-popularly called microbes or germs. They are far too small to be seen by the naked eye. The important infectious diseases of cats are indicated in the table. This importance is not necessarily because the disease commonly occurs, although some do, but also because of the severity of the illness and its public health significance, i.e. the risk of it being transferred to human contacts. More information about these diseases is given later.
The other diseases listed are either uncommon, or else produce only mild signs of illness, if any.
Viruses you will see that most of the important infectious diseases are due to viruses. The common condition, feline urological syndrome, which was mentioned previously, is placed in squire brackets in the list because, although an important condition, it is not clear how significant viruses are in its causation. Certainly, current veterinary opinion regards dry cat food as being at least as important, if not more so, in its development then viral infection.
Reoviruses, though isolated form cases of feline respiratory diseases, do not appear to play a major role in the condition. Aujesky’s disease (pseudo-rabies) is seen in North America and most other counties, particularly in rural areas, but not in Britain or Australia. It effects the brain of many species including cats, but not humans. It is generally believed that most cats, become infected by eating already infected rats. An infected cats become excited, news persistently, salivates but cannot swallow, and frequently shows signs of intense itching, often scratching an area raw. Death invariably occurs within thirty-six hours of these signs appearing, whether treatment is given or not. In many respects the disease resembles rabies, though it runs a shorter course and attacks on humans are not a feature of it.
Table I Infectious Diseases of Cats:
VIRAL DISEASES
• Feline infectious enteritis (FIE) = feline panleukopenia (FPL)
• Feline respiratory disease (FRD) =feline influenza (cat ‘flu)
• Feline viral rhinotrachetiis (FVR)
• Feline calicivirus disease (FCD)
*Feline reovirus infection
* Feline leukaemia
* Feline infectious peritonitis (FIP)
* Rabies
* Pseudorabies (=Aujesky’s disease)
* [Feline urological syndrome (FUS)]
FUNGAL DISEASES
*Ringworm (=dermaomycosis)
Candidiasis (=moniliasis)
Mycetoma (=maduromycosis)
Cryptococcosis
Coccidioidomyccosis
Histoplasmosis
BACTERIAL DISEASES
*Feline infectious anaemia (FIA) =feline haemobartonellosis
*[Trench mouth (=Vincent’s stomataitis)]
Feline respiratory disease (FRD) = feline influenza (cat ‘flu)
Feline pneumonitis
Mycoplasm infection
Tetanus
Tuberculosis (TB)
Salmonellosis
Nocardiosis
Actinomycosis
Listeriosis
Pseudo tuberculosis
Feline leprosy
PROTOZOAN DISEASES
*Toxoplasmosis
Other forms of coccidiosis
Giardiasis
Entamoebiasis
Bacteria: There are a very limited number of bacterial species which produce specific diseases in the cat and these are shown in the table. A further small number of other bacteria (of which staphylococci, streptococci, pasteurellae, E. coli, proteus and pseudomonas are the most important) are responsible for causing a variety of disease at different sites of the body (e.g. pyodermas, arthritis, enteritis, mastitis, pharyngitis, otitis, etc.). In terms of the total numbers of the animals affected with disease, this later group is far and away the most important, but the disorders which they produce are not classified as infectious diseases. In general they are regarded as normal inhabitants of the body (especially on the skin and bowel) which only cause disease when its defenses are impaired.
Feline infectious anaemia (otherwise called feline haemobartonellonis) and trench mouth (or Vincent’s stomataitis) are two common conditions which specific causes. Trench mouth (so-called because the condition was common in soldiers in the trenches during World War I) is due to a combination of spirochete and fusiform bacteria, and produce inflammation of the gums (gingivitis) and a painful mouth with halitosis. Untreated, it can result in destruction of bone and loss of the teeth. It is reputedly more common in the Siamese breed.
Mycoplasms and Chlamydia are bacterial agents that may sometimes play a part, though a relatively miner one, in the development of feline respiratory disease (cat ‘flue). (At times, Mycoplasms may also possibly cause abortions in cats.)
Tetanus (lockjaw) is a rare condition in the cat, as are the chronic conditions of Nocardosis, Actinomycosis (both of which chiefly affect the lungs), listeriosis and pseudo tuberculosis.
Tuberculosis (TB) is also are in cats in those countries where the general incidence of the disease in man and animals is low. However, cases do arise, usually due to drinking infected ‘raw’ (i.e. untreated)cows’ milk, but sometimes caught from owners. Feline Salmonellosis is an unusual, though highly contagious, disease causing gastro-enteritis and fever. Cats suffering from tuberculosis or Salmonellosis can transmit these diseases to humans, and they represent a considerable public health risk.
Feline leprosy is an uncommon, chronic disease reported from most countries and caused by a bacterium similar to that responsible for tuberculosis. It produces multiple, soft nodules in the skin which are painless but which frequently ulcerate.
Fungi: The most widespread fungal condition of the cat is undoubtedly ringworm, which affects the hair, skin and nails. Candidiasis, due to yeast (Candida albicans), very occasionally produces lesion on the skin and in the mouth. The other fungal diseases mentioned occur principally in certain regions of North America. They are rare, and all develop slowly.
Cryptococcosis principally affects the respiratory and nervous systems, Mycetoma affects the skin and nose and the other three listed generally involve the respiratory tract, causing wasting with a chronic cough and high temperature.
Protozoa: Of the parasitic protozoa which may infect the cat, few produce any ill effects. However, toxoplasmosis can result severe illness at times, affecting both the cat and other species which may become infected.
