Decoded: Why are black, white and yellow fungal infections on the rise now?

Mucormycosis, an epidemic within a pandemic, has thrown a new challenge with over 11,000 cases reported across India as on May 25. Mucormycosis is a serious fungal infection, sometimes also called “black fungus”. Other fungal infections, including yellow and white ones, are also being detected in Covid-19 patients. What are these infections, why are their cases rising and how does one protect against them? Let’s find out.

What are black, white and yellow fungal infections?

Mucormycosis, as defined by the Indian Council of Medical Research (ICMR), is a fungal infection that mainly affects people who are on medication for other health problems that reduces their ability to fight pathogens. It is called black fungus since these white fungal colonies have black dots.

Cases of white fungal infections are also being seen in patients with Covid history. The disease, called Candidiasis, is caused by a type of fungus called Candida. “It can occur in the intestine, nailbed or oral cavity. Prolonged use of antibiotics and depressed immune system can lead to this infection,” says Anil Arora, head of gastroenterology at Sir Ganga Ram Hospital, New Delhi. While few cases of white fungus have been reported, its symptoms are said to be similar to Covid-19 infection. The infection can cause organ damage, impact the brain, digestive and respiratory organs, kidneys and private parts. 

There’s also the yellow fungus, or Aspergillosis, but the jury is out on whether it should be classified as a separate category of fungal infection. Its common symptoms include weight loss, loss of appetite and lethargy. Symptoms can become severe over time and include pus leakage, sunken eyes, organ failure, slow healing of wounds and tissue necrosis (cells in living tiss­ues die prematurely). Its detect­ion is difficult and often delayed. 

Randeep Guleria, director of Delhi’s All India of Medical Sciences (AIIMS), is not in favour of using terms like black, yellow and white fungus, which, he earlier said, can mislead and create confusion.

Are these some new fungi?

No, these have been around. The Centre for Disease Control and Prevention (CDC), US, says: “Mucormycetes, the group of fungi that cause mucormycosis, are present throughout the environment, particularly in soil and in association with decaying organic matter, such as leaves, compost piles, and animal dung... Most people come in contact with microscopic fungal spores every day… These fungi aren’t harmful to most people. How­ever, for people who have weakened imm­une systems, breathing in muco­rm­ycetes spores can cause an infection in the lungs or sinuses, which can spread to other parts of the body.”

The yellow fungus disease is also caused by a common mould, Aspergillus, that lives indoors and outdoors. Most people breathe in Aspergillus spores every day without falling ill. However, people with weakened immune systems or lung diseases are at a higher risk of developing health problems such as allergic reactions, lung infections and infections in other organs due to Aspergillus.

Candidiasis (white fungus di­sease), meanwhile, is a fungal in­fection caused by a yeast called Ca­ndida. Some species of Cand­ida can cause infection in peop­le. Candida normally lives on the skin and inside the body, in plac­es such as the mouth, throat, gut and vagina, without causing any problems. Candida can cau­se in­fections if it grows out of control or if it ent­ers deep into the body (for example, the blood­stream or inte­r­nal organs like the kidney, heart, or brain).

Why are these fungal infections on the rise now?

Mucormycosis is a rare disease, but an unusually high number of cases in the last month are attributed to the kind of treatment being given to Covid patients coupled with their comorbidities such as uncontrolled diabetes (high sugar) and suppression of the immune system because of the excessive steroids being prescribed. Prolonged ICU stay, along with pre-existing conditions such as malignancy or organ transplant, also makes people susceptible to this disease. Opinion over whether the use of industrial oxygen and humidified water in oxygen therapy causing fungal infections is divided in the medical fraternity. Guleria recently said there was no link with the oxygen therapy; various doctors, however, feel this is yet to be established.

Similarly, for the other two infections, a suppressed imm­u­ne system and overuse of antibiotics are the leading factors. Mai­ntaining personal hygiene (es­­­­­pecially oral hygiene and kee­p­ing body parts clean and dry in case of diabetics) can be a means of avoiding such infections.

Doctors say recovered Covid patients need to be in touch with their medical practitioner on when to taper off the steroid dose, and that this should be done quickly. Aggressive monitoring of blood sugar is another preventive measure.

What is the treatment and how to manage the disease? 

One of the first things to do is to control diabetes and reduce the use of steroids with an aim to discontinue it rapidly. Any immunomodulating drugs (that stimulate or suppress the immune system) have to be discontinued. All the necrotic tissue has to be surgically removed.

ICMR, in its advisory, suggests antifungal therapy for four-six weeks. While Ampho­tericin B is being used for the treatment of mucormycosis, Echinocandin is the group of drugs needed for the treatment of invasive candidiasis.

When to suspect the disease? 

Symptoms to watch out for in patients of Covid-19, diabetes or those who are immunosuppressed (on chemotherapy or after organ transplant) include sinusitis, nasal blockade, blackish or bloody nasal discharge and localised pain on the cheek bone. One-sided facial pain, numbness or swelling, blackish discolouration over bridge of nose or palate, thrombosis and necrosis, blurred vision, toothache, chest pain are some of the symptoms that should be investigated.

What preventive measures can be taken?

A government advisory lists various precautions that people can take such as using masks while visiting dusty places such as construction sites, wearing clothing that covers arms, legs, feet while handling soil, moss, manure, besides ensuring good personal hygiene.