Tourism implications of cryptococcus gattii in the southeastern USA
In 2007, the first confirmed case of Cryptococcus gattii was reported in the state of North Carolina, USA. An otherwise healthy human immunodeficiency virus (HIV) negative male patient presented with a large upper thigh cryptococcoma in February, which was surgically removed and the patient was started on long-term high-dose fluconazole treatment. In May of 2007, the patient presented to the Duke University hospital emergency room with seizures. Magnetic resonance imaging (MRI) revealed two large central nervous system (CNS) lesions found to be cryptococcomas based on brain biopsy. Prior chest computed tomography (CT) imaging had revealed small lung nodules indicating that C. gattii spores or desiccated yeast were likely inhaled into the lungs and dissemination occurred to both the leg and CNS. The patient’s travel history included a visit throughout the San Francisco, CA region in September through October of 2006, consistent with acquisition during this time period. Cultures from both the leg and brain biopsies were subjected to analysis. Based on phenotypic and molecular methods, both isolates were C. gattii, VGI molecular type, and distinct from the Vancouver Island outbreak isolates. Based on multilocus sequence typing (MLST) of coding and non-coding regions and virulence in a heterologous host model, the leg and brain isolates are identical, but the two differed in mating fertility. Two clinical isolates, one from a transplant recipient in San Francisco and the other from Australia, were identical to the North Carolina clinical isolate at all markers tested. Closely related isolates that differ at only one or a few non-coding markers are present in the Australian environment. Taken together, these findings support a model in which C. gattii VGI was transferred from Australia to California, possibly though an association with its common host plant E. camaldulensis, and the patient was exposed in San Francisco and returned to present with disease in North Carolina.
