Fungi and Candidiasis in Pets

Study Notes

Yeast forms have predisposing factors in dogs or cats with local or disseminated candidiasis, including Diabetes Mellitus (DM), immunosuppressive drugs, and broad-spectrum antibacterial drugs.

Some fungi are opportunistic, causing disease under predisposing conditions such as DM, immunosuppressive therapy, malignancy, burns, and immunodeficient diseases like AIDS.
Examples of opportunistic fungi include Candidiasis, Aspergillosis, and Cryptococcosis.

Aspergillosis is characterized by oral and upper respiratory disease, Pyothorax, and inhalation of spores as a route of transmission.
The infection can extend to the central nervous system (CNS) through the cribriform plate of the ethmoid bone.
Ingestion of spores leads to colonization and invasion of the gastrointestinal tract, resulting in intra-abdominal involvement.
Clinical signs include:
- Fever
- Respiratory signs such as dyspnea and tachypnea
- Ocular signs
- Lameness
- Skin lesions
- Peripheral lymphadenopathy

Multifocal, pale, tan to white nodules within kidneys, liver, pancreas, and pleura
Granulomatous or pyogranulomatous inflammation with abundant intralesional fungal hyphae in various tissues
Infarcts (secondary to thrombi) containing fungal elements found in the spleen, kidneys, and liver
Fibrinoid necrotizing vasculitis with associated hemorrhage
Mottled and congested lung lobes
Serosanguinous pleural effusion
Splenic infarction

Caused by Microsporum and Trichophyton spp
Most common species affecting dogs and cats are Microsporum canis and Trichophyton mentagrophytes
Clinical diagnosis:
- Examination of the haircoat with an ultraviolet lamp (Wood's lamp)
- Some dermatophyte species, including M.canis, glow yellow-green under the lamp