Infectious conditions


Aspergillosis is an opportunist fungal infection. In the dog it generally presents as a nasal and frontal sinus infection and dolichocephalic breeds seem predisposed. In cats the condition is much less common and presents as a systemic disease with variable organ involvement.


Blastomycosis is systemic fungal infection, caused by Blastomyces dermatitidis seen primarily in North America. The lungs are the site of initial infection and from there it may spread to the lymphatics, skin, eyes and bones. Dogs are more commonly infected than cats, young, male, large sporting-breed dogs living close to water being at greatest risk.


Coccidiomycosis is a systemic fungal infection, caused by Coccidioides immitis, seen primarily in the desert regions of North America. Infection originates in the lungs but may disseminate. Young, male, large-breed dogs kept outside seem predisposed, possibly due to increased chance of contact with the pathogen.


Cryptococcosis is a systemic fungal infection, caused by Cryptococcus neoformans, which is found worldwide and may be spread by pigeons. It infects a wide range of mammalian species but is most commonly seen in the cat. Clinical signs may reflect nasal, respiratory, central nervous system, ocular or cutaneous involvement.


The causal organism, Histoplasma capsulatum, is a saprophytic soil fungus. It is uncommon and occurs mainly in the central USA. Clinical signs include fever, anorexia, weight loss, cough, dyspnoea and ocular and skin lesions.

Mycobacterial infections

Mycobacteria are aerobic, acid-fast bacteria with each species having a variation in host affinity and disease potential. Tuberculosis is caused by M. tuberculosis, M. bovis, M. micron or M. avium. The organisms cause granulomas and the site of formation determines the symptoms. Respiratory disease is more common in the dog, cutaneous or alimentary disease in the cat. Treatment is not always recommended as the disease has zoonotic potential.

Parvovirus enteritis

See under Gastrointestinal conditions.

Pneumocyst/s carinii infection

A protozoal infection which may result in pneumonia in the presence of immunosuppression (see also Haematological/immunological conditions).

Infectious conditions of the skin

See under Dermatological conditions.