Ecologic Niche Modeling of Blastomyces dermatitidis in Wisconsin

Abstract

BackgroundBlastomycosis is a potentially fatal mycosis that is acquired by inhaling infectious spores of Blastomyces dermatitidis present in the environment. The ecology of this pathogen is poorly understood, in part because it has been extremely difficult to identify the niche(s) it occupies based on culture isolation of the organism from environmental samples.Methodology/Principal FindingsWe investigated the ecology of blastomycosis by performing maximum entropy modeling of exposure sites from 156 cases of human and canine blastomycosis to provide a regional-scale perspective of the geographic and ecologic distribution of B. dermatitidis in Wisconsin. Based on analysis with climatic, topographic, surface reflectance and other environmental variables, we predicted that ecologic conditions favorable for maintaining the fungus in nature occur predominantly within northern counties and counties along the western shoreline of Lake Michigan. Areas of highest predicted occurrence were often in proximity to waterways, especially in northcentral Wisconsin, where incidence of infection is highest. Ecologic conditions suitable for B. dermatitidis are present in urban and rural environments, and may differ at the extremes of distribution of the species in the state.Conclusions/SignificanceOur results provide a framework for a more informed search for specific environmental factors modulating B. dermatitidis occurrence and transmission and will be useful for improving public health awareness of relative exposure risks.

Geodemographic Features of Human Blastomycosis in Eastern Wisconsin

“…Overall, the distribution of blastomycosis case home sites in eastern Wisconsin in our study matched closely with a map of the predicted geographic distribution of cases in this region based on ecologic niche modeling. 41 Our study has shown an association between blastomycosis and occupation as a machinist, autoworker, construction worker, truck driver or in other machinery/auto-related businesses on both univariable and multivariable analyses. Residence in close proximity to auto-related businesses was associated on univariable analysis only.…”

Update on Fungal Disease: From Establish Infection to Clinical Manifestation

“…Blastomycosis is a potentially fatal infection in humans, dogs and other mammals caused by the thermally dimorphic fungi Blastomyces dermatitidis [184]. It is frequent in adults around 40 years but uncommon in children, and is more predominant in male patients due to occupational factors [185].…”

“…In the lungs there may be an asymptomatic infection, a localized pneumonia, or severe acute respiratory distress syndrome (ARDS). The yeasts that escape phagocytosis can spread to other tissues such as bone, central nervous system, liver, spleen, bone marrow, skin and genitourinary tract [184]. There are also reports of sexually transmitted infections, by intrauterine route and through bites from infected dogs [185,[187][188][189].…”

Variabilités bioclimatiques et distribution spatiale des herbacées fourragères dans le Moyen-Bénin (Afrique de l’Ouest)

“…L'idée générale derrière MaxEnt est de trouver une distribution de probabilités, définie sur la zone d'étude, qui satisfait à un ensemble de contraintes dérivées des données d'occurrence de l'espèce. Chaque contrainte exige que la valeur prévue d'une variable environnementale soit dans un intervalle de confiance de sa moyenne empirique (Reed et al, 2008 Quant à Andropogon tectorum, elle est très fortement distribuée dans la partie méridionale, moyennement présente dans la partie centrale, avec une probabilité d'aire de distribution très faible dans la partie méridionale ( Figure 2d). …”