NEW DELHI - More and more patients in India who have recovered from Covid-19 are finding that they have to battle yet another pathogen.

Doctors across the country are reporting a surge in a rare fungal infection known as mucormycosis among those cured of Covid-19 as well as those recovering from it, adding to India's burden amid its ongoing acute health crisis.

Colloquially referred to as "black fungus", mucormycosis is a highly fatal disease caused by a group of moulds called called mucormycetes that are commonly found in the environment, such as in soil or decaying organic material.

Most people have the immunity necessary to fight it off, but the fungus can find easy entry into those who are immunosuppressed, most commonly through inhalation, with its spores spreading rapidly from sinuses and infecting other body tissues.

"It is worrying because it is something that spreads rapidly in the patient's body," said Dr Roshni Nambiar, an ear, nose and throat (ENT) surgeon based in Mumbai who has operated on some mucormycosis patients.

"The time between a person being diagnosed and potentially not making it can be the span of a couple of days," she told The Straits Times. "It is really aggressive."

In Ahmedabad's Civil Hospital, the number of mucormycosis cases has already crossed more than 200 since April this year. Doctors treated around 150 such patients between January 2020 and March 2021. The hospital has had to set up separate wards to accommodate these patients, adding around 30 to 40 beds daily since the past week.

On Friday (May 14), even as the government and health workers continued to battle an ongoing devastating second wave of coronavirus, India's health minister Dr Harsh Vardhan tweeted a set of dos and don'ts for better management of mucormycosis patients. The country on Friday reported 343,144 new coronavirus cases over the last 24 hours, taking its total caseload past the 24 million mark, with another 4,000 deaths added to its tally.

Dr Maqsood Ali Khan, an ENT and skull base surgeon in Mumbai, told ST he has seen a rise in mucormycosis patients as well. He operated on three such patients last year but in the last two months, has had to operate on around 15 mucormycosis patients.

"I have removed sinus tissues, I have removed eyes, I have removed palate bones… it depends upon the extent of the disease," he said.

Patients require timely surgery to remove infected and dead tissues in order to prevent the fungus from spreading to other parts of the body such as the brain and causing fatalities. This is combined with anti-fungal drug therapy that usually lasts six to eight weeks.

A surge in mucormycosis cases is not entirely out of place, given the higher number of Covid-19 cases in India during the current second wave of infections. Such patients, with their lower levels of immunity, provide a fertile ground for the fungus to proliferate.

Steroids, prescribed to Covid-19 patients to reduce lung inflammation, also suppress immunity and cause a rise in sugar levels. The second wave has seen a pronounced trend in self-medication among those recovering at home, leading to concerns of excessive use of steroids.

Uncontrolled diabetes is another contributing factor, as it provides a conducive environment for the mucormycetes fungi, which is known to thrive in high-glucose, high-iron, and acidic conditions. This correlation with diabetes is particularly of concern for India, a country that is estimated to have the second-highest diabetic population in the world after China.

Patients even risk catching the fungi from contaminated water while using oxygen concentrators.

The surge in mucormycosis patients has also led to a shortage of Amphotericin B - the anti-fungal drug prescribed for such patients. In a statement on Wednesday, the government said it is working with manufacturers to ramp up production of the drug, and added that it is increasing imports as well.

Dr Bela Prajapati, head of the ENT department at Ahmedabad's Civil Hospital, said even patients who had recovered from Covid-19 must check their blood sugar levels every week, and recommended nasal endoscopy for those who report common symptoms associated with mucormycosis such as facial pain or drooping eyelids.