On 27 May 2021, the Government of India invoked the Epidemic Diseases Act of 1897 and declared a nationwide epidemic. The day before, India had reported a total of 11,717 cases of a newly emerging infection. India’s states were hereafter required to notify the Union Ministry of Health of all new victims of this illness. Just as the second wave of the coronavirus pandemic appeared to be receding, growing numbers of Covid-19 survivors were being diagnosed throughout India with a rare fungal infection known as mucormycosis and more widely referred to by the media and members of the public as the “black fungus”.
Mucormycosis is an uncommon infection that is caused by several species of fungi collectively known as Mucormycetes, which belong to the order Mucorales. These fungi are widely distributed in nature, being normally found in soil and in decaying organic matter of either plant or animal origin (compost, leaves, manure) and usually cause little, if any, harm to humans. Infection results from the inhalation by susceptible individuals, with weak immune systems, of fungal spores in inspired air. Direct person-to-person spread does not occur.
The dominant form of mucormycosis in India is the rhino-cerebral form. The infection usually commences in the nasal passages and paranasal sinuses and then progresses rapidly to involve the face, orbit, upper jaw, and eventually the brain. This spread of infection is facilitated by the invasion of blood vessels. Death may follow involvement of the brain and its venous sinuses, which may lead to headache, confusion, seizures, and eventually coma. In the earlier stages, the symptoms may include facial numbness, pain or swelling; nasal discharge, bleeding or blockage; swelling and redness around the eye; blurred or double vision; and numbness and loosening of the upper teeth. These symptoms usually affect only one side of the face to start with. As the infection spreads, the eye may bulge outward and the eyeball may become immobile, while black areas may appear in the roof of the mouth and inside the nose.
The Mucormycetes normally establish themselves in poorly controlled diabetics and others with severely depressed immunity, such as people with cancer or AIDS. In the context of the current pandemic, the Indian Council of Medical Research (ICMR) has identified four major risk groups of Covid-19-positive patients. These include those who have either been treated with steroids, required a prolonged intensive care unit stay, have a pre-existing medical condition (diabetes; kidney or heart failure), or are on medication that suppresses the immune system.
The earlier the diagnosis is made and treatment begun, the better the outcome. Surgical removal of all infected and dead tissue is essential, and a course of anti-fungal drugs, given as a series of intravenous infusions of amphotericin B, is needed to eradicate the fungus. Treatment is a team effort, requiring collaboration between a number of specialties. Surgical treatment is usually carried out by an ENT surgeon, after the extent of spread of the disease has been determined by endoscopic examination of the nasal passages and paranasal sinuses and biopsy, followed by CT or MRI scanning. This surgery often turns out to be rather disfiguring. Effective treatment of mucormycosis in India has unfortunately been hampered by both the high cost and the scarcity of supply of amphotericin B, particularly of less toxic forms of the drug.
The question is why India has been disproportionately affected by the “black fungus”. It seems that the second, and much more devastating, wave of Covid-19 in India has encouraged frenzied efforts at controlling the virus, with many citizens taking over their own care in the absence of reliable healthcare facilities to turn to. The unregulated and widespread use of steroids, often in high doses and for prolonged periods, may have suppressed the immune systems of those treated and increased their susceptibility to the fungus, especially in those with pre-existing diabetes. This misuse of steroids contravenes the RECOVERY trial recommendation for low doses of dexamethasone for short periods of up to ten days in people with severe Covid-19 pneumonia requiring ventilatory support.
In addition, contaminated oxygen cylinders and ventilator systems may have allowed the fungus to establish itself within hospitals and clinics. Open-market and black-market purchases of both medical and industrial-grade oxygen by members of the public may have further enabled this process within the wider community. By contrast, in the Western world, oxygen is treated as a prescription-only medication, and requires clear indications for its use, which must be monitored and adjusted to the patient’s blood oxygen levels.
The mucormycosis epidemic can be considered as a problem at least partly created by humans and their attempts at ill-judged treatment. The Covid-19 pandemic and the superimposed mucormycosis epidemic have provided India with a rationale for the better regulation of the sales, supply and use of drugs. Some good has to come out of an otherwise depressing pandemic, and this seems to be a good time to act constructively for a better future.
Ashis Banerjee