Here are the top 10 facts on the Black Fungus infection:
The Indian Council of Medical Research (ICMR) said at the weekend that doctors treating COVID-19 patients, diabetics and those with compromised immune systems should watch for early symptoms including sinus pain or nasal blockage on one side of the face, one-sided headache, swelling or numbness, toothache and loosening of teeth.
The disease, which can lead to blackening or discolouration over the nose, blurred or double vision, chest pain, breathing difficulties and coughing blood, is strongly linked to diabetes.
Covid-19 patients more susceptible to contracting the fungal infection include those who used steroids during their virus treatment, and those who had prolonged stays in hospital ICUs, the ICMR added.
And diabetes can in turn be exacerbated by steroids such as dexamethasone, used to treat severe COVID-19. "There have been cases reported in several other countries - including the UK, the US, France, Austria, Brazil and Mexico, but the volume is much bigger in India," David Denning, a professor at Manchester University and an expert at the Global Action Fund for Fungal Infections charity, told news agency Reuters.
Media reports have pointed to cases in Maharashtra and state capital Mumbai, and Gujarat. Aparna Mukherjee, a scientist at ICMR, said, "It's not something to panic about, but you have to be aware of when to seek consultation."
Arunaloke Chakrabarti, head of the Centre of Advanced Research in Medical Mycology in Chandigarh, said that even before COVID-19, mucormycosis was more common in India than in most countries, "partly because of the millions who have diabetes".
P Suresh, head of opthalmology at Fortis Hospital in Mulund, Mumbai, said his hospital had treated at least 10 such patients in the past two weeks, roughly twice as many as in the entire year before the pandemic. All had been infected with COVID-19 and most were diabetic or had received immunosuppressant drugs. Some had died, and some had lost their eyesight, he said.
The Health Ministry on Sunday released an advisory on how to treat the infection. "The cases of mucormycosis infection in Covid-19 patients post-recovery is nearly four to five times than those reported before the pandemic," Ahmedabad-based infectious diseases specialist Atul Patel, a member of the state's COVID-19 taskforce, told news agency AFP.
Some 300 cases have been reported so far in four cities in Gujarat, including its largest Ahmedabad, according to data from state-run hospitals. The state ordered government hospitals to set up separate treatment wards for patients infected with "black fungus" amid the rise in cases.
Treatment involves surgically removing all dead and infected tissue and administering a course of anti-fungal therapy. But Yogesh Dabholkar, an ear, nose and throat specialist at Mumbai's DY Patil Hospital, told AFP that the drugs used to treat those infected with the fungus were expensive.