Subcutaneous Mycoses

FUNGI

Pythiosis

• Mycotic swamp fever

Sporotrichosis

• Sporothrix schenckii

• Occurs in soil, wood and vegetation

• Worldwide

• Exogenous infections through wounds

• Causes subcutaneous nodules or granulomas
  • Nodules ulcerate discharging pus

• Spread via the lymphatics

• The bones and viscera can be involved which terminates in mortality
  • This is rare
  • Reported in dogs and horses

• Affects dogs, horses, cats, monkeys, mules, camels, donkeys, cattle, fowl and rodents
  • Most commonly seen in horses as an ascending lymphocutaneous infection of the legs

• Single cell, cigar shaped
  • Usually found within neutrophils
  • Yeast cell clusters with peripheral eosinophilic rays can be seen in tissue sections

• Stained using PAS, fluorescent antibody and Calcofluor White

• Latex agglutination and immunodiffusion serology can be performed

• Grows on Blood agar and Sabouraud's Dextrose agar in one to three weeks

• At 37°C:
  • Colonies are smooth, cream to tan coloured and soft
  • No mycelium can be seen

• At 25°C to 27°C:
  • Colonies turn from white and soft to tan to brown to black
  • Leathery, wrinkled and coarse
  • Mycelium can be seen as branching septate hyphae
  • Conidiospores can also be seen

• Potassium iodide treatment orally
  • 5-fluorocytosine and amphotericin B can also be used

Further Links

• Pathology of subcutaneous mycoses

• Antifungal Drugs