Emergence of Cryptococcus gattii-- Pacific Northwest, 2004-2010

Abstract

Cryptococcus is a genus of fungi, of which two species, Cryptococcus neoformans and Cryptococcus gattii, cause nearly all human and animal cryptococcal infections. Whereas C. neoformans primarily affects persons infected with human immunodeficiency virus (HIV) worldwide, C. gattii primarily affects HIV-uninfected persons in tropical and subtropical regions. In December 2004, a case of human C. gattii infection was reported in Oregon, associated with an outbreak on Vancouver Island and in mainland British Columbia, Canada. A second C. gattii case was reported in Oregon in 2005, and 12 more cases were reported in 2006 and 2007. In 2008, in response to the emergence of C. gattii in the United States, CDC, state and local public health authorities, and the British Columbia Centre for Disease Control (BCCDC) formed the Cryptococcus gattii Public Health Working Group. States began collecting epidemiologic information on patients and sending isolates to CDC. By July 2010, a total of 60 human cases had been reported to CDC from four states (California, Idaho, Oregon, and Washington) in the Pacific Northwest. Among 52 patients for whom travel history was known, 46 (88%) said they had not traveled to British Columbia or any other C. gattii--endemic areas, suggesting they acquired the infection locally. Among 45 patients with known outcomes, nine (20%) died because of C. gattii infection, and six (13%) died with C. gattii infection. Physicians should consider C. gattii as a possible etiology of a cryptococcal infection among persons living in or traveling to the Pacific Northwest or traveling to other C. gattii--endemic areas.