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Emmonsiosis
Emmonsiosis, also known as emergomycosis, is a systemic fungal infection that can affect the lungs, generally always affects the skin and can become widespread.[1][2] The lesions in the skin look like small red bumps and patches with a dip, ulcer and dead tissue in the centre.[4] It is caused by the Emergomyces species, a novel dimorphic fungus, previously classified under the genus Emmonsia.[3] These fungi are found in soil and transmitted by breathing in its spores from the air.[1] Inside the body it converts to yeast-like cells which then cause disease and invade beyond the lungs.[1] Diagnosis is by skin biopsy and its appearance under the microscope.[5] It is difficult to distinguish from histoplasmosis.[3][6] Treatment is usually with amphotericin B.[3] Emmonsiosis can be fatal.[3] The disseminated type is more prevalent in South Africa, particularly in people with HIV.[3] Signs and symptomsGenerally, all cases have involvement of the skin.[5] The lesions look like small red bumps and patches with a dip, ulcer and dead tissue in the centre.[4] There may be several lesions and their distribution can be widespread.[1] The lungs may be affected.[3][4] CauseIt is caused by the Emergomyces species, a novel dimorphic fungus, previously classified under the genus Emmonsia.[3][7] Following a revised taxonomy in 2017 based on DNA sequence analyses, five of these Emmonsia-like fungi have been placed under the separate genus Emergomyces.[3] These include Emergomyces pasteurianus, Emergomyces africanus, Emergomyces canadensis, Emergomyces orientalis and Emergomyces europaeus.[3][8] Emergomyces africanus was previously known as Emmonsia africanus, which has similar features to Histoplasma spp. and the family of Ajellomycetaceae.[6] The disease has been observed among people who have a weakened immune system and risk factors include HIV, organ transplant and steroid use.[1][3] MechanismThe fungus is found in soil and is released in the air.[1] Transmission is by breathing in fungal spores from the air.[1] Inside the body it converts to yeast-like cells which then cause disease and invade beyond the lungs.[1] In people with HIV, Emmonsiosis has been associated with Immune reconstitution inflammatory syndrome following initiating antiretroviral treatment.[1] DiagnosisDiagnosis is by skin biopsy and its appearance under the microscope.[5] Differential diagnosisGenerally, it is difficult to distinguish from histoplasmosis.[6] Other conditions that appear similar include tuberculosis,[5] blastomycosis, sporotrichosis, chicken pox, Kaposi's sarcoma and drug reactions.[4] TreatmentTreatment usually includes amphotericin B.[3] PrognosisIt can be fatal.[5] EpidemiologyThe disseminated type is more prevalent in South Africa, particularly in people with HIV.[5] HistoryThe disease was thought to be a rare condition of the lung.[2] Early cases may have been misdiagnosed as histoplasmosis.[6] Other animalsThe genus Emmonsia can cause adiaspiromycosis, a lung disease in wild animals.[9] References
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