Cryptococcus Gattii Infection (C. gattii)
2015 Case Definition

Background

Cryptococcus is a ubiquitous fungal pathogen that causes primarily meningitis and pneumonia. The incidence of cryptococcal infection in the United States has been estimated at 0.4–1.3 cases/100,000/year. Two species of Cryptococcus cause the vast majority of human infections: C. neoformans and C. gattii. C. neoformans has a clear predilection for causing disease in persons in whom the immune system is impaired, and today an overwhelming proportion of C. neoformans infections occur in immunocompromised persons. In contrast, C. gattii was, until recently, considered a disease exclusive to immunocompetent persons living in tropical and subtropical regions of the world. It is an emerging pathogen in the United States, best known for having caused an outbreak in the Pacific Northwest, but locally acquired infections have been identified in several other states during the past five years. Early data from endemic areas suggested that C. gattii differed not only in epidemiology and clinical presentation from C. neoformans, but might also have different susceptibilities to antifungal agents and require more aggressive and lengthier antifungal therapy than C. neoformans infections.

Laboratory Criteria For Diagnosis

Any of the following:

• Isolation of Cryptococcus gattii from a clinical specimen; or
• Detection of Cryptococcus gattii-specific nucleic acid in clinical specimen; or
• Demonstration of Cryptococcus gattii in a clinical specimen by immunohistochemistry; or
• Result of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF), performed on a clinical specimen, specific for Cryptococcus gattii.

Criteria to Distinguish a New Case from an Existing Case

Cryptococcal infection is presumed to be chronic. A person may be a case only once. A new case is one that has not been previously reported.

Confirmed

A case meeting the laboratory criteria.