Blastomycosis diagnosed in a nonhyperendemic area

Area of Science:

• Medical Mycology
• Infectious Diseases
• Public Health

Background:

• Blastomycosis is caused by Blastomyces dermatitidis, a fungus endemic in northern Wisconsin.
• The disease presents as localized outbreaks and sporadic cases in endemic zones.

Purpose of the Study:

• To investigate blastomycosis cases diagnosed outside the hyperendemic region of Wisconsin.
• To analyze demographic and clinical features of blastomycosis in a non-endemic setting.

Main Methods:

• Electronic health records were queried for blastomycosis diagnoses (ICD-9 codes) over 32 years.
• Patient records were reviewed for clinical and demographic data.
• Blastomycosis incidence data from Wisconsin and Minnesota (2002-2006) were analyzed.

Main Results:

• Twenty-six blastomycosis cases were identified at Gundersen Health System.
• Average time from symptom onset to positive B. dermatitidis specimen was 51 days.
• 73% of patients were initially treated for bacterial pneumonia; incidence in the service area was 0.17 per 100,000.

Conclusions:

• Delayed diagnosis of blastomycosis outside endemic areas can lead to mortality.
• Blastomycosis should be considered in the differential diagnosis for unexplained respiratory illness in non-endemic regions.