Emerging Epidemics in Transplant: Histoplasmosis, Blastomycosis, and Paracoccidioidomycosis

Abstract

The endemic fungi are a group of thermally dimorphic fungi that occupy specific defined environmental ranges. They count Histoplasma, Blastomyces, Paracoccidioides, Coccidioides, Talaromyces, Emergomyces, and Sporothrix among their number. In the environment, they exist as molds, and at body temperature, they transform into their pathogenic yeast form (or, in the case of coccidioidomycosis, into a specialized structure called a spherule). Histoplasma, Blastomyces, and Paracoccidioides are covered in this chapter. Transplant recipients are at increased risk for severe and disseminated infection with these pathogens. Histoplasmosis and blastomycosis usually manifest as pulmonary disease. Extrapulmonary disease can occur with or without concomitant pulmonary disease in immunocompromised hosts. Commonly infected sites include the liver, spleen, lymph nodes, bone marrow, gastrointestinal tract, and skin. Skin involvement is especially common in blastomycosis. Paracoccidioidomycosis may present in an acute disseminated form in young patients. However, in 90% of symptomatic paracoccidioidomycosis, pulmonary chronic disease is observed, which is a reactivation of prior acquired infection. Oral mucosa and skin are common sites of dissemination in chronic disease. Diagnosis of endemic mycoses is difficult and often delayed. Combining various diagnostic modalities is usually needed. The treatment of choice for all the endemic mycoses are amphotericin B and the azoles. In general, treatment must be given for a prolonged period (frequently a year or more) in order to prevent a relapse.

Persistent fever after coronavirus disease 2019 in liver/kidney transplant recipient

“…Histoplasmosis is a systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum endemic to certain regions of the Americas 30,31 . Most individuals with H. capsulatum infection undergo asymptomatic dissemination, leaving foci of viable H. capsulatum dormant in many organs, kept in check by an appropriate cell‐mediated immune response.…”