NEW DELHI — Doctors in India are concerned about an increasing number of potentially fatal fungal infections affecting either people who have Covid-19 or those who have recently recovered from the disease.

The condition, known as mucormycosis, has a high mortality rate and was present in India before the pandemic. It is caused by a mold that thrives in wet environments and can attack through the respiratory tract, potentially eroding facial structures and harming the brain.

The condition is relatively rare, but doctors and medical experts say it seems to be infecting some Covid patients whose weakened immune systems and underlying conditions, particularly diabetes, leave them vulnerable.

Some experts attribute the fungal infections to an increased use of steroids to treat hospitalized patients. Another factor could be that, with hospitals overwhelmed in this second wave of the pandemic, many families are self-medicating and applying oxygen therapy at home without the proper hygiene, experts say.

In the western state of Maharashtra, which includes the commercial hub of Mumbai and has been badly devastated by the pandemic, local news media reported that around 200 patients who had recovered from Covid were being treated for mucormycosis and that eight had died.

In Gujarat, a western state north of Maharashtra, the state government ordered the allocation of separate wards in hospitals for the treatment of the infection, and said it had put purchase orders for 5,000 doses of amphotericin b, a medicine used to treat it. Infections have also been reported in hospitals in the country’s capital, New Delhi.

Health experts are keeping close tabs on the situation. “We have heard that in some areas, people who are Covid-infected or recovered suffer from mucormycosis, but there is not big outbreak of it,” Dr. V.K. Paul, who heads India’s Covid task force, said last week. “We are watching and monitoring.”

“It is a fungus that has a strong relation to diabetes,” he added. “If the person is not diabetic, it is very uncommon that the person would have mucormycosis.”

Many less populous countries have higher percentages of the diabetes, but only one — China, with a population even larger than India’s 1.38 billion — has a higher raw number of diabetics. In India, more than 10 percent of the adult population has the condition, or 77 million people. China has more than 116 million adult diabetics, or 9 percent, according to the 2019 International Diabetes Foundation Atlas.

Dr. K. Srinath Reddy, who leads the Public Health Foundation of India, said a large number of the recent reported mucormycosis cases are of hospitalized coronavirus patients who have been discharged after their recovery.

“You are using steroids to reduce the hyperimmune response, which is there in Covid,” Dr. Reddy said. “But you are reducing the resistance to other infections.”