Today, the world faces increasing variants of Covid-19, each more virulent than the original strain. Other diseases, too, have started to spin off the scourge.
Black fungus or mucormycosis is one of them. The term is not new, as it was first identified by Arnold Paltauf in 1885.
However, it is only now that people are becoming increasingly aware of it due to its association with Covid-19.
Mucormycosis has been dubbed "black fungus" because it causes blackening or discolouration of the nose.
It is a rare but opportunistic fungal infection with a high morbidity and mortality rate.
The spores can be found in fruits, soil, faeces and are present in the air.
Spores can be inhaled through the nose, mouth or even enter the body through a cut in the skin. Once they grow in the nose, they destroy bones in the nose and sinuses and can even lead to blindness.
Once the fungus enters the cranial cavity, it can block major arteries and veins, resulting in major life-threatening brain strokes.
Our body's defence mechanisms keep the fungi at bay. However, a weakened immune system will allow these organisms to unleash morbid and lethal infections. People who are at risk include diabetics, as well as those suffering from leukaemia, renal failure, protein-calorie malnutrition and cirrhosis.
The disease also attacks patients who have undergone transplants and those on corticosteroid and immunosuppressive therapy.
Local factors that can spark the disease include burns, knife wounds, insect bites, needle pricks and trauma.
Mucormycosis may be also triggered by the use of steroids, a life-saving treatment for severe and critically ill Covid-19 patients.
Steroids reduce inflammation in the lungs for Covid-19 and appear to help stop some of the damage that can happen when the body's immune system goes into overdrive to fight off coronavirus.
But they also reduce immunity and push up blood sugar levels in both diabetic and non-diabetic Covid-19 patients, thereby helping the spread of black fungus.
Diabetes lowers the body's immune defences, coronavirus exacerbates it, and then steroids which help fight Covid-19 act like fuel to the fire.
When it comes to Covid-19, there are two types of mucormycosis observed in patients: rhino-orbito-cerebral mucormycosis and pulmonary mucormycosis.
In rhino-orbito-cerebral mucormycosis, the infection begins from the nose and spreads along the sinus passage to infect the eyes and brain.
Nose blockage, unusual nasal discharge, facial swelling, pain and numbness are some of the initial symptoms. Over time, this may result in headache, eye pain, blurred vision and partial blindness.
Pulmonary mucormycosis primarily affects the lungs and the respiratory system. Those who catch it develop symptoms such as fever, cough, shortness of breath and chest pains.
As the infection spreads and it is not treated in time, it may lead to the development of pleural effusion, also known as "water in the lungs".
To prevent a black fungus infection we offer the following suggestions.
First, the public should maintain strict oral hygiene. This is especially important for those recuperating from a Covid-19 infection.
This is because the intake of steroids and other medication enables bacteria in the mouth to grow, hence brushing twice or thrice a day and the use of mouthwash can help stave off the infection.
Patients are also advised to change their toothbrush once they test negative and keep rinsing their mouth regularly.
Second, diabetic patients must undergo frequent periodic testing of their sugar level.
Third, the public should avoid exposure to dust and moisture and keep their distance from soil, trees and plants. If they display symptoms, they should immediately report themselves to the medical authorities.
Fourth, to keep sinuses clear the people should try steam inhalation.
Fifth, the people are strongly advised to not self-medicate, especially if it involves the use of steroids.
If everyone plays a part in preventing it, black fungus would not take hold in Malaysia as it has in India and other parts of the world.
The writer is an associate professor in Oral Medicine and Maxillofacial Radiology, Faculty of Dentistry, AIMST University