Blastomycosis

Abstract

Blastomycosis is a serious fungal disease of humans and other mammals caused by environmentally acquired infection with geographically restricted, thermally dimorphic fungi belonging to the genus Blastomyces. The genetic and geographic diversity of these pathogens is greater than previously appreciated. In addition to Blastomyces dermatitidis and the cryptic species Blastomyces gilchristii, which cause blastomycosis in mid-western and various eastern areas of North America, atypical blastomycosis is occasionally caused by Blastomyces helicus in western parts of North America and Blastomyces percursus in Africa. Blastomycosis is acquired by inhalation of the conidia that are produced in the mold phase; in the lungs, temperature-dependent transformation occurs to the yeast phase. In this form, the organism is phagocytized by macrophages and can spread hematogenously to various organs causing disseminated infection. Pulmonary disease is most common and varies from mild, self-limited infection to severe, potentially fatal adult respiratory distress syndrome. Disseminated infection is manifested primarily by skin lesions, but many other organs can be involved. Diagnosis is established by growth of the organism in culture; however, a tentative diagnosis can be made quickly by histopathological identification of the classic yeast form in tissues or by finding Blastomyces antigen in urine or serum. Blastomycosis is treated initially with amphotericin B when the disease is severe, involves the central nervous system, or the host is immunosuppressed. Itraconazole is recommended for primary therapy in mild-to-moderate infection and for step-down therapy after initial amphotericin B treatment. Voriconazole and posaconazole can be used for patients in whom itraconazole is not tolerated.

Immunotherapy against Systemic Fungal Infections Based on Monoclonal Antibodies

“…In the yeast form, Blastomyces spp. is phagocytized by macrophages and other immune cells and can spread by blood circulation to other organs, producing a disseminated infection (reviewed in [250,251]). The most common form of Blastomycosis is the pulmonary disease and diverges from patient to patient from mild, self-limited infection to a severe respiratory distress syndrome.…”

“…Itraconazole, voriconazole and posaconazole are recommended as first-line therapy in mild-to-moderate infection. As first-line therapy in severe cases patients are treated with amphotericin B (reviewed by [250,251]).…”

The Role of the Interleukin-17 Axis and Neutrophils in the Pathogenesis of Endemic and Systemic Mycoses

“…These systemic mycoses are caused by a group of thermally dimorphic fungal pathogens belonging to different genera of several species including Histoplasma capsulatum, Coccidioides spp., Blastomyces spp., Paracoccidioides spp., Talaromyces marneffei and the newly described pathogen Emergomyces spp. (Sepuĺveda et al, 2017;Turissini et al, 2017;Kirkland and Fierer, 2018;Cao et al, 2019;Schwartz et al, 2019;Schwartz and Kauffman, 2020). Additionally, these mycoses are usually geographically restricted; thus, histoplasmosis is found worldwide, coccidioidomycosis is endemic in some regions of the United States and some countries of Latin America, blastomycosis is endemic in North America and Africa, paracoccidioidomycosis is restricted to Latin America, talaromycosis is endemic in Asian countries, while emergomycosis has been reported in Africa, Europe, Asia, and North America (Sepuĺveda et al, 2017;Turissini et al, 2017;Kirkland and Fierer, 2018;Cao et al, 2019;Schwartz et al, 2019;Schwartz and Kauffman, 2020).…”

Development of a duplex real-time PCR assay for the differentiation ofBlastomyces dermatitidisandB. gilchristiiand a retrospective study of blastomycosis in New York (2005-2019)

“…With the advancement of molecular tools, several distinct genetic populations were recognized within the Blastomyces genus, and that led to the creation of new species including B. gilchristii (a cryptic species phenotypically indistinguishable from B. dermatitidis) (2,3), B. percursus, and B. silverae (4,5). A rare cause of blastomycosis from B. helicus in western part of North America and B. percursus in Africa was also reported (6,7).…”

“…Outdoor exposure and proximity to water have been associated with blastomycosis (10). Blastomycosis is reportable in only five states in the US, namely Arkansas, Louisiana, Michigan, Minnesota, and Wisconsin (6) . In New York State, Blastomycosis is considered an emerging disease [http://www.nycasm.org/Alerts/Notification_101674.pdf].…”