Emergomycosis is an emerging systemic fungal infection caused by the recently identified genus of thermally dimorphic fungi, Emergomyces. To date, 5 species have been identified: Emergomyces pasteurianus, Emergomyces africanus, Emergomyces canadensis, Emergomyces orientalis, and Emergomyces europaeus. These pathogens are soil-associated molds that convert to yeast cells in vivo. 

Sporadic cases of the disease have been documented worldwide, including North America (Canada: Alberta, Saskatchewan; United States: Arizona, Utah, Colorado, New Mexico), Europe (Italy, Spain, France, the Netherlands, Germany), and Asia (China, India). Within Africa, cases have been described in South Africa and Uganda, with the greatest burden in South Africa, where most infections are attributed to E africanus and primarily present with skin involvement in patients with advanced HIV disease.

The infection occurs mainly in immunocompromised hosts, most frequently in HIV-infected individuals, but also in transplant recipients and in patients with diabetes, hematologic malignancies, or those on chronic immunosuppressive therapy. Transmission is presumed to occur via inhalation of soilborne conidia, which converts to a yeast phase in vivo and may disseminate hematogenously in susceptible individuals.

Clinical presentation is typically disseminated at diagnosis. Cutaneous lesions are the most common manifestation, seen in up to 96% of patients in one study, while pulmonary involvement is present in approximately 88%. Lesions are often widespread and polymorphic. Less commonly, disease may involve the bone marrow, lymph nodes, liver, spleen, and cervix.