Risk factors
Predisposing factors for mucormycosis include conditions where people are less able to fight infection, have a low neutrophil count or metabolic acidosis. Risk factors include poorly controlled diabetes mellitus (particularly DKA), organ transplant, iron overload, such cancers as lymphomas, kidney failure, long term corticosteroid and immunosuppressive therapy, liver disease and severe malnutrition. Other risk factors include tuberculosis (TB), deferoxamine and to a lesser extent HIV/AIDS. Cases of mucormycosis in fit and healthy people are rare.Corticosteroids are commonly used in the treatment of COVID-19 and reduce damage caused by the bodys own immune response to the virus. They are immunosuppressant and increase blood sugar levels in both diabetic and non-diabetic patients. It is thought that both these effects may contribute to cases of mucormycosis. Mechanism
Most people are frequently exposed to Mucorales without developing the disease. Mucormycosis is generally spread by breathing in, eating food contaminated by, or getting spores of molds of the Mucorales type in an open wound. It is not transmitted between people.The precise mechanism by which diabetics become susceptible is unclear. In vivo, a high sugar alone does not permit the growth of the fungus, but acidosis alone does. People with high sugars frequently have higher iron levels, also known to be a risk factor for developing mucormycosis. In people on deferoxamine, the iron removed is captured by siderophores on Rhizopus species, which uses the iron to grow. Diagnosis
There is no blood test that can confirm the diagnosis.
It is the third most common serious fungal infection to infect people, after aspergillosis and candidiasis.Diabetes is the main underlying disease in low and middle-income countries, whereas, blood cancers and organ transplantation are the more common underlying problems in developed countries. As new immunomodulating drugs and diagnostic tests are developed, the statistics for mucormycosis have been changing. In addition, the figures change as new genera and species are identified, and new risk factors reported such as tuberculosis and kidney problems. COVID-19–associated mucormycosis
During the COVID-19 pandemic in India, the Indian government reported that more than 11,700 people were receiving care for mucormycosis as of 25 May 2021. Many Indian media outlets called it "black fungus" because of the black discoloration of dead and dying tissue the fungus causes. Even before the COVID-19 pandemic, rates of mucormycosis in India were estimated to be about 70 times higher than in the rest of the world. Due to its rapidly growing number of cases some Indian state governments have declared it an epidemic. One treatment was a daily injection for eight weeks of anti-fungal intravenous injection of amphotericin B which was in short supply. The injection could be standard amphotericin B deoxycholate or the liposomal form. The liposomal form cost more but it was considered "safer, more effective and [with] lesser side effects".§ The major obstacle of using antifungal drugs in black fungus is the lack of clinical trials. Recurrence of mucormycosis during COVID-19 second wave in India
Pre-COVID mucormycosis was a very rare infection, even in India.