Blastomycosis in 64 Wisconsin Children: Unanticipated Infection Risk and Severity in Urban Residents

Abstract

Background: Blastomycosis, an endemic mycosis of immunocompetent individuals, is typically seen after exposure to waterways within rural wooded regions. It is not considered a disease of urban environments. Infection can be solely pneumonic or disseminate to skin, bone or central nervous system. Unknown factors influence disease acquisition and severity in children. Methods: We analyzed acquisition risks and disease characteristics of blastomycosis in children seen at a tertiary care center from 1998 to 2018 to identify potential exposure sources, measure disease severity and assess the effect of race upon disease severity. Results: Of 64 infected children, mean age was 12.9 years, with median time to diagnosis 38.5 days. About 72% were male, 38% resided in urban counties and 50% had typical environmental exposure. Isolated pulmonary infection occurred in 33 (52%). The remainder had evidence of dissemination to skin (N = 13), bone (N = 16; 7 clinically silent) and cranium (N = 7; 3 clinically silent). Infection was moderate/severe in 19 (30%). Two children (3%) died. About 79% of children with moderate/severe disease (P = 0.008) and 71% of urban children (P = 0.007) lacked typical environmental exposure. Comparing children from urban counties to other residences, 63% versus 5% were black (P < 0.001) and 71% versus 35% developed extrapulmonary dissemination (P = 0.006). Moderate/severe disease was seen in 7/17 (42%) black children but only 12/47 (26%) children of other races (P = 0.23). Conclusions: Blastomycosis, can be endemic in urban children in the absence of typical exposure history, have frequent, sometimes clinically silent, extrapulmonary dissemination and possibly produces more severe disease in black children.

Disseminated Blastomycosis in an African American immunocompetent pediatric patient: Lessons learned

“…Certain racial groups—including African Americans, Native Americans, Asians of Hmong ancestry, and the Indigenous Canadian population—have an increased incidence and severity of disseminated fungal infections 2,5 . Recent studies have suggested that genetic differences in innate immunity among certain ancestral backgrounds may explain this increased susceptibility to fungal infections 6 .…”

“…Clinical manifestations of disseminated blastomycosis vary widely and include asymptomatic infection (up to 50% of cases), pneumonia (53%–75% of cases), disseminated disease involving any organ (25%–40% of cases), or death 1,3,5 . Disseminated blastomycosis can occur in immunocompetent or immunocompromised individuals, while disseminated histoplasmosis is typically an opportunistic infection 2,4 . The skin is the most common extrapulmonary organ system affected, with about 60% of disseminated infections having cutaneous lesions 5 .…”

“…Blastomycosis is a systemic pyogranulomatous disease caused by the thermally dimorphic fungi Blastomyces , found in regions bordering the Mississippi and Ohio River Valleys, Great Lakes, and southeastern United States 1,2 . Blastomyces exists as spore‐releasing mold in the environment, which transforms into pathogenic yeast when inhaled into the lungs.…”

“…Lymphohematogenous spread can occur, leading to disseminated disease. 3 About 3%-10% of blastomycosis cases occur in the pediatric population, 2,4 and overall mortality has been estimated to be 4%-9%. 2,3,5 Rapid diagnosis and treatment of disseminated blastomycosis improves patient morbidity and mortality.…”

“…Certain racial groups-including African Americans, Native Americans, Asians of Hmong ancestry, and the Indigenous Canadian population-have an increased incidence and severity of disseminated fungal infections. 2,5 Recent studies have suggested that genetic differences in innate immunity among certain ancestral backgrounds may explain this increased susceptibility to fungal infections. 6 Therefore, eliciting racial background, as well as other risk factors such as recent travel history, occupational history, and recreational activities is key, as these factors may increase patient vulnerability to fungal infections.…”