Additional Isolations of Blastomyces Dermatitidis from Natural Sites

Abstract

The ecological niche of Blastomyces dermatitidis has not been established. This paper describes the repeat isolation of this pathogenic fungus from organic debris collected at a natural site and another, previously not reported, isolation. Although the precise environmental source of this pathogen still cannot be defined, each isolation of this fungus from a natural site adds to the understanding of the ecology of this organism.

Non-Rural Point Source Blastomycosis Outbreak Near a Yard Waste Collection Site

“…4 Recent rainfall was reported prior to the environmental recovery of B. dermatitidis following several documented point source outbreaks. 15,25,[33][34][35] All of these environmental conditions existed prior to and during the estimated exposure period of this outbreak.…”

“…Environmental conditions that support B. dermatitidis growth in geographically-restricted microfoci are apparently short-lived. 34 When sporadic cases or outbreaks of blastomycosis are identified, environmental conditions may no longer exist to support growth of B. dermatitidis making environmental isolation difficult. Despite thousands of attempts, successful isolation of the mold from the environment has only occurred 21 times.…”

Geodemographic Features of Human Blastomycosis in Eastern Wisconsin

“…Having nearby natural, open or nondomicile features such as park land, forests or fields may increase the risk of a home site being associated with blastomycosis. Additional epidemiologic and environmental studies (hampered, of course, by the difficulty in isolating Blastomyces from the environment 30 ) are required to determine if automobile/machinery-related occupations or nearby businesses increase the risk for acquisition of blastomycosis. Further elucidation of the environmental determinants of Blastomyces distribution and propagation could lead to more specific preventive recommendations.…”

“…[27][28][29][30][31] For these reasons, we used home addresses of blastomycosis cases to explore environmental associations of this disease in our previous Wisconsin studies. In one such study, home addresses were compared to certain geographic features utilizing a geographic information system.…”

Disease-Causing Fungi in Homes and Yards in the Midwestern United States

“…55,56 Evidence includes case studies 54,57 and repeated cases of blastomycosis at the same home site with different families; 58 several studies that failed to implicate specific outdoor or occupational activities with acquisition of blastomycosis in most cases; [59][60][61] and the isolation of B. dermatitidis from an abandoned house 62 and 20 m from a human home in northern Wisconsin. 47 Evidence, therefore, has been largely circumstantial.…”