BACKGROUND: Cryptococci are emerging fungal pathogens in Oregon and the Pacific Northwest. C. gattii was once thought limited to tropical areas but has been isolated in animals and humans in Oregon since 2008. The most common route of exposure is inhalation from the environment; infection can cause severe disease. To track the health impact of these emerging fungal pathogens, all cryptococcal infections became reportable in Oregon in 2011. We describe the different types of cryptococcal infections reported, as well as the proportion of cases identified by cryptococcal antigen testing alone —i.e., without culture.
METHODS: Laboratory information was collected from clinical laboratories electronically. All Cryptococcosis cases were investigated by the local public health authorities and data entered into a central Oregon Health Authority database
RESULTS: Two hundred twenty cases of Cryptococcal infection were reported to the Oregon Health Authority during 2012–2015. Of those, 63 (28%) were C. neoformans, 52 (24%) were C. gattii, 25 (11%) were C. albidus, 10 (4.5%) were C. laurentii, 9 (4.1%) were C. uniguttulatus and 1 (0.5%) were C liquefaciens and 11 (0.5%) were diagnosed by histopathology alone. A culture-independent method — viz., cryptococcal antigen testing — was the case-defining laboratory procedure in 49 (22%) of cases identified; in the absence of an isolate, these could not be speciated. Over the past 3 years, the number of cases diagnosed by antigen testing only has increased from 4 cases in 2012, 9 cases in 2013, 14 cases in 2014 and 22 cases in 2015 identified by cryptococcal antigen testing only has increased.
CONCLUSIONS: Cryptococcosis reporting has revealed a substantial number of human infections in Oregon caused by a variety of subtypes. The increased use of cryptococcal antigen as a diagnostic tool limits the epidemiologic understanding of cryptococcal subtypes as causes of infection and potentially limits the identification of new cryptococcal pathogens. Encouraging healthcare providers to pursue isolate identification along with the use of cryptococcal antigen will further illuminate the epidemiology of this emerging pathogen.