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. 2010 May;118(5):653-8.
doi: 10.1289/ehp.0901448.

Ecological niche modeling of Cryptococcus gattii in British Columbia, Canada

Sunny Mak  1 , Brian Klinkenberg, Karen Bartlett, Murray Fyfe
Affiliations

Ecological niche modeling of Cryptococcus gattii in British Columbia, Canada

Sunny Mak et al. Environ Health Perspect. 2010 May.

Abstract

Background: Cryptococcus gattii emerged on Vancouver Island, British Columbia (BC), Canada, in 1999, causing human and animal illness. Environmental sampling for C.gattii in southwestern BC has isolated the fungal organism from native vegetation, soil, air, and water.

Objectives: Our aim was to help public health officials in BC delineate where C.gattii is currently established and forecast areas that could support C.gattii in the future. We also examined the utility of ecological niche modeling (ENM) based on human and animal C.gattii disease surveillance data.

Methods: We performed ENM using the Genetic Algorithm for Rule-set Prediction (GARP) to predict the optimal and potential ecological niche areas of C.gattii in BC. Human and animal surveillance and environmental sampling data were used to build and test the models based on 15 predictor environmental data layers.

Results: ENM provided very accurate predictions (> 98% accuracy, p-value < 0.001) for C.gattii in BC. The models identified optimal C.gattii ecological niche areas along the central and south eastern coast of Vancouver Island and within the Vancouver Lower Mainland. Elevation, biogeoclimatic zone, and January temperature were good predictors for identifying the ecological niche of C.gattii in BC.

Conclusions: The use of human and animal case data for ENM proved useful and effective in identifying the ecological niche of C.gattii in BC. These results are shared with public health to increase public and physician awareness of cryptococcal disease in regions at risk of environmental colonization of C.gattii.

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Figures

Figure 1
Figure 1
Geographic distribution of human and animal cryptococcosis and isolation of C. gattii from the environment in southwestern BC. Cases are mapped by address of residence and include travel-related cases to Vancouver Island. Figure adapted from Kidd et al. (2007b), by permission from the American Society for Microbiology.
Figure 2
Figure 2
C. gattii ecological niche prediction maps based on the distribution of human (A) and animal (B) cases and positive environmental sampling locations from permanently established sites (C) in BC.
Figure 3
Figure 3
Validation of C. gattii ENM predictions on the BC mainland based on the model input of animal cases. The distribution of mainland human (A) and animal (B) cases and positive environmental samples (C) are displayed in the insets. Not shown are 1 of 11 human cases, 1 of 13 animal cases, and 2 of 4 positive environmental sampling sites, which are located in the northern Sunshine Coast area, outside of the inset map’s extent.
See this image and copyright information in PMC

References

    1. Agriculture and Agri-Food Canada. SLCS 2.2. 1995. [accessed 27 March 2006]. Available: http://sis.agr.gc.ca/cansis/nsdb/slc/v2.2/intro.html.
    1. Bartlett KH, Kidd SE, Kronstad JW. The emergence of Cryptococcus gattii in British Columbia and the Pacific Northwest. Curr Fungal Infect Rep. 2007;10(1):108–115. - PubMed
    1. BC (British Columbia) Ministry of Forests and Range, Research Branch. Biogeoclimatic Ecosystem Classification, Version 6.0. 2006. [accessed 27 March 2006]. Available: http://www.for.gov.bc.ca/hre/becweb/resources/maps/gis_products.html.
    1. Byrnes EJ, III, Bildfell RJ, Frank SA, Mitchell TG, Marr KA, Heitman J. Molecular evidence that the range of the Vancouver Island outbreak of Cryptococcus gattii infection has expanded into the Pacific Northwest in the United States. J Infect Dis. 2009;199(7):1081–1086. - PMC - PubMed
    1. Casadevall A, Perfect JR. Cryptococcus neoformans. Washington, DC: American Society for Microbiology; 1998. Ecology of Cryptococcus neoformans; pp. 41–70.

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