Alexander Fleming, the Scottish bacteriologist and Nobel laureate, in 1928 noticed the green mold, Penicillium notatum accidentally growing in the culture dish of Staphylococcus bacteria and it clearing the zone around the mold. This chance observation revolutionised the world with series of antibiotics with penicillin nucleus at its core. Another fungus “Claviceps purpurae “which is commonly known as Ergot and is responsible for plant disease with the same name that grows on grasses , especially on Rye , changed the face of maternity and child birth care by its derivative which helped safe labor and addressed bleeding during the process of child birth. The iconic Psychedelic drug , Lysergic acid Diethylamide ( LSD ) is also an ergot derivative and so is the revolutionary cholesterol drug “Statin” . The list is long and equally impressive.
Fungi can produce circumscribed itchy skin lesion on different body parts named, Taenia capitis for head or Taenia corporis for body . Similarly Disfigured nails and nail bed lesions called Onychomycosis , is due to dermatophyte fungi Taenia infection .
A patch of curd coat over tongue, palate , fauces or food pipe’s mucous membranes known as Thrush or candidiasis , are caused by candida , a yeast, often seen in premature neonates and in those kids with poor hygiene or in debilitated adults . They are in general easy to treat.
Other set of diseases are for people who stay at specific geographical locations associated with handling moist soil or those staying in river basin harbouring a set of unique fauna and flora. These fungi cause granulomatous chest diseases or allergies of lung and air passage. They have good prognosis if diagnosed early.
However, it’s the deep invasive systemic forms which are life threatening and are almost always associated with immune suppressed states such as HIV/ AIDS. various Cancers, Autoimmune diseases, failure of kidney, Liver, post-transplant states, premature neonates and now immune dis-regulatory Covid- 19 disease specially in its new delta avatar! Common amongst
these fungi are Aspergillosis due to mold Aspergillus, Tolarimycosis and pneumocystis jiroveci causing difficult to treat pneumonia and at times brain Meningitis ,more often due to Cryptococcal fungal infection .
Black fungus disease which is hogging the headlines following Covid-19 specially in India, is caused by Mucormycetes, present in air everywhere in tropical and subtropical atmosphere. In immune suppressed individuals possibly due to circulating delta variant of covid, concurrent steroid exposure in Diabetics or even in pre diabetics the mucormycetes , famously called “Black Fungus “ develops into fast growing invasive disease . Though fungi are in general a very colourful creature , in this context it is a misnomer and gives wrong impression about the colour of the fungi. Black colour here is of blood deprived dead tissues present around the infected area. It may manifest as only limited invasive form , confined to nose and nasopharyngeal wall or may spread aggressively to involve entire upper respiratory passage, paranasal sinuses and adjoining orbital area containing eye ball and soft tissues surrounding eyes . Sometimes it may spread to adjoining front part of the skull and brain. This Rhino-orbito -cerebral form, is the most destructive and difficult to treat manifestation of the disease and has very poor outcome even after mutilating surgery and prolonged intravenous anti-fungal drugs i.e. Amphotericine B and newer - Azoles.
Such is the threat of fungi on evolution that It is said that “Homo sapiens “have survived on planet earth because their immune system is extremely smart and capable to pass the “Fungal Filter “ !
The author is former Professor and Head, Department of Medicine, RIMS, Ranchi.
