All You Want to Know About Black Fungus

KO Photo By Abid Bhat

Dr M Ashraf Ganie

What is Mucormycosis?

MUCORMYCOIS is a fungal opportunistic infection caused by ubiquitous filamentous fungi belonging to the Mucoraceae family of the order Mucorales, subphylllum Mucormycotina. The most frequently isolated species is Rhyzopus oryzae followed by Rhizopus microsporus and Absidia corymbifera. Black fungi per se are biologically a different category of fungi having melanin in the cell wall. However, mucormycosis is informally referred to as black fungus.

Where Mucormycosis Comes From?

The organism is quite ubiquitous. It is present in the air, leaves and piles of compost, soil and rotting wood. Infections may result from ingestion of contaminated food, inhalation of spores into the nares or lungs or inoculation into disrupted skin or wounds. In developed countries, mucormycosis occurs primarily in severely immunocompromised hosts. In contrast, in developing countries like ours, most cases of mucormycosis occur in poorly controlled diabetics. All-cause mortality rates for mucormycosis range from 40% to 80% with varying rates depending on underlying conditions and sites of infection.

Overall Disease Burden 

The Leading International Fungal Education (LIFE) portal has estimated the burden of serious fungal infections globally. According to their estimate, the annual prevalence of mucormycosis might be around 10,000 cases in the world barring India. After the inclusion of Indian data, the estimate of mucormycosis rose to 910,000 cases globally. So mucormycosis is already far more common in India compared to other countries.

Risk Factors for Mucormycosis 

The major risk factors for these invasive fungal infections include 

Uncontrolled diabetes mellitus, particularly with ketoacidosis

Injudicious use of corticosteroids 

Organ or bone marrow transplantation

Neutropenia and malignant haematological disorders. 

Injection drug use

Trauma/burns 

Malnutrition

Why Mucormycosis is Showing a Surge in COVID-19 Patients? 

The widespread reports of mucormycosis in the country suggest that it is not coming from a single contaminated source and does not have a single explanation. It is an evolving condition that will unfold in the coming days. The proposed reasons may be highlighted as under:

Indiscriminate use of steroids without a proper rationale is probably the principal reason behind this increased risk of mucormycosis.

Prevalence of DM and DKA in COVID-19 are higher compared to the national prevalence of type 2 DM and DKA in the general population. 

Alteration of iron metabolism occurs in severe COVID-19. Severe COVID-19 is a hyper-ferritinemic state and high ferritin levels lead to excess intracellular iron that generates reactive oxygen species resulting in tissue damage. 

The resultant tissue damage due to hypoxemia and cytokine storm also leads to the release of free iron into the circulation. Iron overload and excess free iron seen in acidemic states are one of the key and unique risk factors for Mucormycosis. 

Another possible explanation for the association between COVID-19 and MCR is the “endothelialitis” observed in severe COVID-19.Endothelial adhesion and penetration is critical early steps in Mucormycosis. 

The other plausible reasons could be poor maintenance of oxygen humidifiers, improper use of broad-spectrum antibiotics & other immunosuppressant drugs like tocilizumab.

 It is not illogical to think that the practice of ‘gobar snan’ could be a potential cause of this deadly fungal infection, but this practice of exposure to cow dung is an isolated practice, so it is not wise enough to attribute it to the recent surge. 

Global Scenario of CAM

Isolated cases of CAM have been reported from USA, Brazil and UK. Diabetes mellitus was again the most common predisposing condition in these patients. However, India is presenting a different and unprecedented picture in terms of CAM. Several states in India are experiencing an unexpected surge in cases of mucormycosis in people diagnosed with COVID-19. Gujarat has so far reported the highest number of mucormycosis cases, the other states/cities following are Madhya Pradesh, Odisha, Jaipur, Maharashtra and Uttarakhand. The UT of Jammu and Kashmir has not reported any case of black fungus so far. A high index of suspicion is needed to pick up these cases early. 

When to Suspect Mucormycosis in COVID-19 Patients

Patients with COVID-19 illness in acute , recovering or post-discharge phase with following symptoms/signs should be suspected of having mucormycosis :

Nasal blockage or congestion , bloody or brown/black nasal discharge 

Facial pain , numbness or swelling 

Persistent headache, orbital pain

Toothache , loosening of maxillary teeth , jaw involvement 

Double/blurred vision with pain, skin lesion and eschar( necrotic lesion) 

Persistent fever, cough , chest pain , bloody sputum or worsening of respiratory symptoms  

How to Prevent CAM

Important preventive steps to be followed, especially in diabetic patients with COVID-19:

·       Reasonable glycemic control

·       Timely treatment of DKA

·       Rational use of steroids – correct timing , correct dose and duration

·       Use clean , sterile water for humidifiers during oxygen therapy

Dr Mohammad Ashraf Ganie is DM/MD/PhD guide at SKIMS Srinagar and AIIMS New Delhi. He is also Editor of Diabetes and Obesity Journal.

How to Manage Mucormycosis?

Suspected case should undergo appropriate radio-imaging study like MRI of paranasal sinuses with brain contrast study for Rhino-orbito-cerebral(ROCM) and plain CT thorax for pulmonary Mucormysosis. Involvement of multi-disciplinary team is suggested–Physician, Endocrinologist, ENT/Eye specialist, Pulmonologist and last but not the least a Gastroenterologist. GI manifestations though not much, but these patients may need percutaneous endoscopic gastrostomy (PEG) to provide a means of feeding when nasopharyngeal region is severely affected. Suspected and confirmed mucormycosis are emergencies and require rapid action. Surgical debridement Plus Immediate treatment initiation of medical treatment with Liposomal amphotericin B is recommended. 

Mucormycosis is not a new disease and has resurged in Covid subjects owing to multiple factors including hyperglycaemia, steroid use etc. Jammu and Kashmir has reported only few cases of black fungus among COVID-19 patients so far. Although healthcare workers should look for early symptoms of this infection in order to initiate timely management but they should not instil undue fear and anxiety among the public. Self-medication with steroids especially among those who are home isolated must be discouraged. To revise the dose and duration of steroids among hospitalised patients by the attending doctor is indispensable. Agencies should ensure an adequate stock of Liposomal Amphotericin B, the primary drug, in the market to treat mucormycosis. 

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