[16] These fungi are common in soils, decomposing organic matter (such as rotting fruit and vegetables), and animal manure, but usually do not affect people.

[15] Risk factors include diabetes with persistently high blood sugar levels or diabetic ketoacidosis, low white blood cells, cancer, organ transplant, iron overload, kidney problems, long-term steroids or use of immunosuppressants, and to a lesser extent in HIV/AIDS.

[8] Preventive measures include wearing a face mask in dusty areas, avoiding contact with water-damaged buildings, and protecting the skin from exposure to soil such as when gardening or certain outdoor work.

[25] The face may look swollen on one side, with rapidly progressing "black lesions" across the nose or upper inside of mouth.

[6][27] Affected skin may appear as a dusky reddish tender patch with a darkening centre due to tissue death.

[5][32] The fungal spores are present in the environment, can be found on items such as moldy bread and fruit, and are breathed in frequently, but cause disease only in some people.

[5] In addition to being breathed in and deposited in the nose, sinuses, and lungs, the spores can also enter the skin via blood or directly through a cut or open wound, and can also grow in the intestine if eaten.

[15][32] Once deposited, the fungus grows branch-like filaments which invade blood vessels, causing clots to form and surrounding tissues to die.

[5] Outbreaks have also been linked to hospital bed sheets, negative-pressure rooms, water leaks, poor ventilation, contaminated medical equipment, and building works.

[33] One hypothesis suggests that the spread of fungal spores in India could be due to fumes generated from the burning of Mucorales-rich biomass, like cow dung and crop stubble.

[34] Predisposing factors for mucormycosis include immune deficiencies, a low neutrophil count, and metabolic acidosis.

[13][9] Risk factors include poorly controlled diabetes mellitus (particularly DKA), organ transplant, iron overload, such cancers as lymphomas, kidney failure, liver disease, severe malnutrition, and long term corticosteroid and immunosuppressive therapy.

[32] Mucormycosis is generally spread by breathing in, eating food contaminated by, or getting spores of molds of the Mucorales type in an open wound.

[5] Tests may also include culture and direct detection of the fungus in lung fluid, blood, serum, plasma and urine.

[18] A reverse halo sign in a person with a blood cancer and low neutrophil count is highly suggestive of mucormycosis.

[10] Treatment involves a combination of antifungal drugs, surgically removing infecting tissue and correcting underlying medical problems, such as diabetic ketoacidosis.

[32] Possible complications of mucormycosis include the partial loss of neurological function, blindness, and clotting of blood vessels in the brain or lung.

[27] As treatment usually requires extensive and often disfiguring facial surgery, the effect on life after surviving, particularly sinus and brain involvement, is significant.

[20] In addition, the figures change as new genera and species are identified, and new risk factors reported such as tuberculosis and kidney problems.

[1] In 1943, its association with poorly controlled diabetes was reported in three cases with severe sinus, brain and eye involvement.

[1] When cases were reported in the United States in the mid-1950s, the author thought it to be a new disease resulting from the use of antibiotics, ACTH and steroids.

In a review of cases involving the lungs diagnosed following flexible bronchoscopy between 1970 and 2000, survival was found to be better in those who received combined surgery and medical treatment, mostly with amphotericin B.

[12] A number of cases of mucormycosis, aspergillosis, and candidiasis, linked to immunosuppressive treatment for COVID-19 were reported during the COVID-19 pandemic in India in 2020 and 2021.

Five had abnormal kidney function tests, three involved the sinus, eye and brain, three the lungs, one the gastrointestinal tract, and in one the disease was widespread.

This is because unlike non-COVID-19 patients with severe diabetes, cancer or HIV, the recovery time required for the main cause of immune suppression is temporary.

[12] Other countries affected included Pakistan,[55] Nepal,[56] Bangladesh,[57] Russia,[58] Uruguay,[59] Paraguay,[60] Chile,[61] Egypt,[62] Iran,[63] Brazil,[64] Iraq,[65] Mexico,[66] Honduras,[67] Argentina[68] Oman,[69] and Afghanistan.

[21][75] The first international congress on mucormycosis was held in Chicago in 2010, set up by the Hank Schueuler 41 & 9 Foundation, which was established in 2008 for the research of children with leukaemia and fungal infections.

A confirmed case was defined as 1) necrotizing soft-tissue infection requiring antifungal treatment or surgical debridement in a person injured in the tornado, 2) with illness onset on or after May 22 and 3) positive fungal culture or histopathology and genetic sequencing consistent with a mucormycete.

[76][77] In 2014, details of a lethal mucormycosis outbreak that occurred in 2008 emerged after television and newspaper reports responded to an article in a pediatric medical journal.

[80] Another study attributed an outbreak of hospital-acquired mucormycosis to a laundry facility supplying linens contaminated with Mucorales.