Cryptococcus is a commonly found pathogen that infects patients with weakened immune systems.

Cryptococcus neoformans is a yeast-like fungus that gained prominence in the medical community due to its tendency to sicken the immunocompromised. Present in soil world-wide, the opportunistic pathogen (an organism that preys on patients with weakened immune system) enters a host through inhalation of air-borne spores and has the potential to cause cryptococcal meningitis by infecting the membranes surrounding the brain and spinal cord or cryptococcosis, an infection of multiple tissues. Cryptococcus is not transmissible from person-to-person and its long incubation period before causing
clinically-significant symptoms often creates difficulty in pinpointing the source of the fungus. The name “Cryptococcus” means “hidden sphere” and pathologists employ special histological stains to visualize and identify the organism within tissue. Each round fungal organism is surrounded by a colorless mixture of protein and carbohydrates. The application of a mucin stain colors the capsule of Cryptococcus red and facilitates its microscopic identification. This photomicrograph shows cryptococcal
infection of the liver, consistent with cryptococcosis.