In May, several Indian states declared a “black fungus” epidemic, as cases of the fatal infection shot up in patients recovering from Covid-19. Now, the disease seems to be spreading to other countries -- so what is this disease exactly?
Black fungus is a type of fungal infection which is affecting patients of COVID-19. The number of black fungus infections are rising with each passing day, with over 40,000 infections in India to date. Cases have already been reported Chile, Uruguay, Egypt and Iraq
Mucormycosis, also known as black fungus, is caused by fungi of group Mucorales. Mucormycosis grows fast in the body and can defeat the immune system, especially in patients whose immune system are already under great pressure (such as immunocompromised patients or those suffering from a different disease, like COVID-19 or diabetes). Most people are likely to come into contact with the fungus at some point in their everyday lives, but a healthy immune system will normally keep the infection at bay.
Mucormycosis is caused by inhalation of fungal spores called sporangiospores. Once in the body, sporangiospores increase in size by swelling and germinate, producing hyphae (hyphae are the branching filaments that make up the mycelium of a fungus). This production of hyphae triggers an invasion of tumor cells into blood vessels, cell injury resulting in premature cell death and blockage of blood vessels by blood clots. Hyphae can’t be killed by natural killer cells, macrophages or monocytes, which makes them very dangerous.
The disease mainly impacts organs such as sinuses, brain and lungs. Its symptoms include but aren’t limited to pain in chest, swollen face on one side, shortness of breath, cough, fever, congestion in sinus, headache, diarrhea, blood in stool, pain in stomach, nausea, vomiting, and black colored lesions inside mouth or on nasal bridge.
Mucormycosis occurs in five different forms:
- cutaneous mucormycosis; this occurs when due to a trauma to the skin, the fungus enters the skin and causes the infection. This type of mucormycosis occurs more frequently than the other types in individuals who do not have a suppressed immune system.
- gastrointestinal mucormycosis; here, the infection takes place in stomach.
- disseminated mucormycosis; infection extends via bloodstream to the other parts of the body such as skin, heart and spleen.
- pulmonary mucormycosis; the fungus infects lungs and is common in individuals who have cancer or have had an organ transplanted
- rhinocerebral mucormycosis; this is takes place by infecting brain and sinuses. It is commonly seen in individuals who have diabetes that is not under control or have had kidney transplanted.
Diagnosing, treating, and preventing black fungus disease
The hyphae interact with immune cells in human body, and can be damaged and killed through oxidation. This happens after a neutrophil or monocyte (two types of white blood cells) attach themselves to the filaments of fungus. But by far, the best attempt at dealing with black fungus is diagnosing it early.
Only when diagnosed in time, it can be controlled from spreading to other parts of body. The diagnosis can be done through a number of methods such as imaging, and culture and biopsy. In imaging methods, a computed tomography scan of organs such as sinuses and lungs is done. However, in culture and biopsy method of diagnosis, samples are taken from affected parts of the body through biopsy and are cultured. Using microscopic methods, the cultured samples are visualized to look for filaments having vast, ribbon-like appearance with growth at right angles. These are the two main methods of diagnosis, though there is another, called differential diagnosis which involves distinguishing fungus from similar looking organisms such as aspergillosis.
Since black fungus can be life-threatening, early diagnosis and treatment are essential. The treatment can be done in several ways, either by individual courses of action, or by combining two or more modes. Sometimes, these approaches includes surgical removal of tissues that are infected by the fungus, use of antifungal drugs and control of risk factors such as uncontrolled hyper glycemia. Immune system suppressing drugs may be given to individuals who are suffering from an underlying condition that predisposes them to a black fungus infection.
Black fungus infection can be prevented despite there being many risk factors for it. Doctors suggest various preventive measures to prevent individuals from getting a black fungus infection whether they have COVID-19 or not. The most important preventive measure is to wear a face mask which will prevent accidental inhalation of fungal spores.
One should also avoid regions with dusty environment such as a construction site. Individuals who are into gardening or have work involving coming into contact with soil or manure should wear full clothes having full sleeves to avoid contact with fungus. Blood glucose and sugar levels should be kept under control. Individuals who are on steroids should be closely watched for signs for black fungus infection.
Furthermore, steroids should not be consumed without a doctor’s advice. In individuals with a suppressed immune system, anti-fungal drugs can be given to prevent the fungal infection from occurring.
The bottom line
One can never be too careful when it comes to black fungus.
Black fungus infection is dangerous by its very nature, but in conjunction with other diseases, it can be life threatening, and we're seeing thousands and thousands of severe cases in India -- with doctors fearing that it could continue to spread to other areas.
Even the surgery needed to remove infected tissue causes severe disfigurement and can lead to lasting problems. While no one can know for certain who will be infected with black fungus, individuals with an underlying disease should be extremely careful and closely monitor themselves for signs of black fungus. Aggressive investigations are helpful in detecting the infection on time. Treatment should be done in a timely manner to control the infection and prevent it from affecting other organs.