Mucormycosis/Black Fungus Disease in COVID Patients: Introduction, Ca

Mucormycosis/Black Fungus Disease in COVID Patients: Introduction, Causative agent, Sign and symptoms, Lab Diagnosis, Treatment, Prevention and Control

Introduction of Mucormycosis/Black Fungus Disease

Mucormycosis/black fungus disease (previous zygomycosis) is a fungal infection that principally affects people who are immunocompromised or on medication for other health problems that reduce their ability to fight environmental pathogens. It may be suspected in COVID-19 patients, diabetics, or immunosuppressed individuals having the following conditions-

Sinusitis – nasal blockage or congestion, nasal discharge (blackish/bloody), local pain on the cheekbone
One-sided facial pain, numbness, or swelling
Blackish discoloration over the bridge of nose/palate
Toothache, loosening of teeth, jaw involvement
Blurred or double vision with pain; fever, skin lesion; thrombosis and necrosis (eschar)
Chest pain, pleural effusion, hemoptysis, worsening of respiratory symptoms

Mode of transmission of Mucormycosis/Black Fungus Disease

Mucormycosis/black fungus disease mode of transmission is via spores. Sinuses or lungs of such individuals get affected after fungal spores are inhaled from the air or the skin after the fungus enters the skin through a cut, burn, or another type of skin injury.

Predisposing Factors of Mucormycosis/Black Fungus Disease

Mucormycosis/black fungus disease is common in people who have the following conditions-

Uncontrolled diabetes mellitus
Immunosuppression by steroids
Prolonged ICU stay
Co-morbidities – post-transplant/malignancy
Voriconazole therapy
the low number of white blood cells (especially neutropenia)
iron overload or hemochromatosis
Skin injury due to surgery, burns, or wounds
Prematurity and low birthweight (for neonatal gastrointestinal mucormycosis)

Causative agents of Mucormycosis/Black Fungus Disease

The causative agents of mucormycosis/ black fungus diseases are as follows-

Rhizopus,
Mucor,
Cunninghamella,
Apophysomyces,
Lichtheimia (formerly Absidia),
Saksenaea,
Rhizomucor, and
other species.

Pathogenicity

Mucormycosis is a serious but rare fungal infection caused by three genera of class micromycetes, Mucor, Rhizopus, and Absidia. These fungi are saprophytes of soil, manure, and decaying vegetables. Mucormycosis mainly affects people who with weakened immune systems. It most commonly affects the sinuses or the lungs after inhaling fungal spores from the air, or the skin after the fungus enters the skin through a cut, burn, or another type of skin injury. Absidia may also cause keratitis. However, it can occur in nearly any part of the body even bone to brain. Gastrointestinal mucormycosis may occur in malnutrition, uremia, and diarrhoeal diseases.

Sign and symptoms of Mucormycosis/Black Fungus Disease

Pain and redness around eyes and/or nose
Fever
Headache
Coughing
Shortness of breath
Bloody vomits
Altered mental status
bloody or blackish mucus emission from the nose
Distinct blackish discoloration on the bridge of the nose
Pain on only one side of the face, cheekbones, numbness
Blurred vision
Pleural effusion

Laboratory Diagnosis of Mucormycosis/Black Fungus Disease

Specimens: Specimens depend on the nature of infection sites. They may be scrapping from the lesions, pus, sputum, nasal discharge, etc.

Direct Microscopy- KOH mount: Presence of fungal elements ( non-septate hyphae)

Histopathological examination: Histological sections stained H & E stain reveal the presence of hyphae.

Culture: Colonies are very fast-growing, cottony to fluffy, white to yellow, becoming dark grey, with the development of sporangia.

Identification using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technique

Molecular techniques targeting different loci i.e. ribosomal targets 18S, 28S and Internal transcribed spacer (ITS); FTR1 gene, cytochrome b

Treatment of Mucormycosis/Black Fungus Disease

Treatment completes in either using antifungal drugs or surgery or both

Useful antifungal drugs are-

Amphotericin B
Posaconazole

Surgery

Removal affected tissue

Prevention and Control of Mucormycosis/Black Fungus Disease

Use masks (N95 respirators) if you are visiting dusty construction sites.
Wear shoes, long trousers, long sleeve shirts, and gloves while doing outdoor activities such as gardening, yard work, or visiting wooded areas.
To decrease the chances of developing a skin infection, clean skin injuries well with soap and water, particularly if they have been exposed to soil or dust.
Control glucose level in hyperglycaemic patient
Monitor blood glucose level post-COVID-19 discharge and also in diabetics
Use steroid properly – correct timing, correct dose, and duration
Use clean, sterile water for humidifiers during oxygen therapy

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