Cryptococcosis

• Over 19 species
  • Cryptococcus neoformans only major pathogen

• Worldwide

• Occurs in high concentrations in pigeon droppings (high creatinine concentration)
  • The pigeon is not infected
  • C. neoformis colonise the droppings after they have been excreted
  • Also found in fruit, milk and soil

• Exogenous, inhaled infection which is generally sporadic (non-contageous)
  • Can also be absorbed via skin penetration and ingestion

• May be a primary pathogen or opportunistic

• Targets the respiratory system
  • Including the paranasal sinuses
  • Also can be systemic, cutaneous, visceral, skeletal or ocular

• Causes sporadic mastitis in cattle
  • Can spread within the herd

• Affects the CNS of dogs and cats
  • paranasal sinuses and pharynx can be infected with dissemination to the CNS and other tissues
    • E.g. Lungs, kidneys and joints
  • Also causes subcutaneous granulomas
  • The tip of the nose is a common site of infection in cats
    • See here

• Causes myxoma-like lesions of the lung and lip in horses

• Causes cryptococcal meningitis in humans

• Also affects dolphins, foxes, ferrets, monkeys, birds, cheetahs and guinea-pigs

• Large yeast with capsule seen using India ink stain

• Stains with PAS (Periodic acis Schiff)

• Gram positive

• Grows on blood agar and Sabouraud's Dextrose agar forming white, granular colonies which become slimy, mucoid and turn creamy/brown within a week

• Species identified by carbohydrate assimilation tests

• Antigen and antibody should be tested for as antibody formed by the body is soon overwhelmed and neutralised by abundent polysaccharide antigen from the capsule in active, systemic infections
  • Latex agglutination for antigen, complement fixation, ELISA and IFAT can be used

Cryptococcosis Learning Resources
Vetstream To reach the Vetstream content, please select	Canis, Felis, Lapis or Equis
Flashcards Test your knowledge using flashcard type questions	Cryptococcosis Flashcards