As coronavirus cases and deaths soared in India recently, doctors began to notice another disturbing trend. Some covid-19 patients who had been released from hospitals were coming back with different symptoms, including sinus pain, blurred vision, black and bloody nasal discharge and a dark discoloration around the nose.

The culprit was a deadly fungal infection called mucormycosis that physicians say is increasingly preying on people with immune systems weakened by covid-19 and the steroids used to treat it.

Though cases of what is known as “black fungus” remain rare, its lethality and increasing prevalence have prompted government warnings, put doctors on high alert and added to the country’s health crisis.

“The death rate from mucormycosis is 50 percent,” said Amarinder Singh Malhi from All India Institute of Medical Science, a public hospital in New Delhi. “The death rate from covid is 2.5 percent. So we have to use these steroids very cautiously.”

Malhi said his hospital had not seen a spike in mucormycosis cases. But about a week ago, a journalist connected him on WhatsApp with a woman who had lost vision in one eye and was going blind in the other.

“I referred that case to the emergency room,” he said, suspecting the woman had mucormycosis. “She needed antifungal drugs immediately.”

Unless treated early, the aggressive fungal infection can often only be stopped with surgery.

One Mumbai-based eye surgeon said he saw 40 mucormycosis cases last month alone, and 11 had to have an eye removed.

“I will be removing her eye to save her life,” the doctor, Akshay Nair, told the BBC shortly before operating on a 25-year-old woman who had recovered from covid three weeks ago only to contract mucormycosis. “That’s how this disease works.”

“I’ve seen 24 cases in 2 weeks!” he tweeted recently. “Scary.”

Nair told the BBC that between December and February, six colleagues in five cities reported 58 cases of the infection, most contracted 12 to 15 days after the patient recovered from covid.

P Suresh, head of ophthalmology at Fortis Hospital in Mulund, near Mumbai, told Reuters his hospital had treated at least 10 mucormycosis patients in the past two weeks — twice as many as in the year before the pandemic. All had been infected with covid-19, he said, and most were diabetic or had received immunosuppressants, such as steroids.

Mucormycosis infections are now four to five times what they were before the pandemic, infectious diseases specialist Atul Patel told AFP.

India has not released nationwide data on mucormycosis cases, but officials say the country is not suffering from a major outbreak.

“It’s not something to panic about, but you have to be aware of when to seek consultation,” Aparna Mukherjee, a scientist at the state-run Indian Council of Medical Research, told Reuters.

Mucor mold spores can be found in soil, manure or the air but normally don’t affect healthy people, doctors say. For the immunocompromised, however, the fungus can be deadly.

“In the pre-covid era, this type of fungus would come in immunocompromised patients, patients with severe diabetes, leukemia, lymphoma and other immunodeficiencies,” Malhi said.

He blamed the recent increase in mucormycosis on the overuse of steroids to stem the pandemic.

“We are seeing a 100 to 200 percent increase in cases in some states,” he said. “We did not see that previously in the first [covid] wave. Now, in the second wave, we are seeing it because we are using steroids more. These steroids are a double-edged sword.”

Prince Surana, a doctor and CEO of several private hospitals in Mumbai, said reports of mucormycosis at other local hospitals had led his group to tighten policies on steroid use that have, so far, prevented black fungus infections.

“We have not been giving steroids ... to every covid patient,” he said, “especially if the patient is susceptible to that type of cross-infection or has a comorbidity, like diabetes.”

Surana said doctors needed to tell covid patients when they are discharged to monitor for symptoms of mucormycosis, such as sinus pain, swelling or numbness, or vision loss — a warning also issued over the weekend by the ICMR.

But the crush of covid cases has made checking on discharged patients more difficult, Surana said, and has also complicated sterilization.

“In normal times we’d fumigate the ICU every 14 days. Now, with covid, complete fumigation is not possible,” he said, adding that his hospitals had compensated by putting extra effort into deep-cleaning surfaces.

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