A rapid rise in cases of mucormycosis, also known as 'black fungus', has added to the challenges faced by India's healthcare system as it deals with a massive second wave of Covid-19 infections.
But what is it, and what's driving the recent rise in cases?
What is 'black fungus'?
Mucormycosis, or black fungus is a fungal infection which causes blackening or discoloration over the nose, blurred or double vision, chest pain, breathing difficulties and coughing blood. The disease has a close link to diabetes, and conditions which compromise the immune system.
Experts have said an overuse of certain drugs to suppress the immune system during the Covid-19 pandemic could be causing the surge in black fungus cases.
Data from the US Centre for Disease Control and Prevention shows mucormycosis has a mortality rate of 54 per cert, which can vary depending on the condition of the patients and the body part affected.
States across India have reported more than 5,000 cases of the otherwise rare disease in recent weeks, mostly in people infected with Covid-19 or recovering from the virus.
Is it contagious?
The disease is not contagious, which means it cannot spread from contact between humans or animals. However, it does spread from fungal spores that are present in the air or in the environment, which are almost impossible to avoid.
"Bacteria and fungi are present in our bodies already, but they are kept in check by the body’s immune system," said Dr Katkeri Bhujang Shetty, head of Narayana Nethralaya, a speciality eye hospital in Bangalore .
"When the immune system goes down because of cancer treatment, diabetes or use of steroids, then these organisms get an upper hand and they multiply," he said.
Is the use of unsanitised oxygen cylinders/ventilators causing the outbreak?
It's hard to say.
Experts say unsanitary conditions could increase the risk of developing the infections.
"There is a lot of contamination in the pipes used for oxygen, the cylinders that are being used, the humidifiers used," said Nishant Kumar, an ophthalmologist at Hinduja Hospital in Mumbai.
"If you are immuno-suppressed, and you have been on these pipes and oxygen for a long period of time, then these infections get much more of an opportunity to get in."
But opinion is divided on this point.
"Hospitals were dirty even before April. We need epidemiological studies to assess why these cases are rising now," said S.P. Kalantri, senior doctor and researcher at the Mahatma Gandhi Institute of Medical Sciences in Maharashtra.
Why is black fungus being noted and not other fungal infections?
Covid-19 has been associated with a wide range of secondary bacterial and fungal infections, but experts say India's second wave of the virus has created a perfect environment for mucormycosis.
Low oxygen, diabetes, high iron levels, immuno-suppression, coupled with several other factors including prolonged hospitalisation with mechanical ventilators, creates an ideal milieu for contracting mucormycosis, researchers wrote in the journal Diabetes & Metabolic Syndrome: Clinical Research & Reviews.
