ABSTRACT
The present review describes about the disease and the fungal agent in brief, and also stresses for establishment of mechanically ventilated hospital wards across the country. Second wave of COVID-19 pandemic in India has been complicated by high infection rate (R-0), 600% jump in medical oxygen demand by COVID hospitals, and after all emergence of Mucormycosis since April-May 2021 leading to fatal complications. Mucormycosis is a very rare infection in humans. It is caused by exposure to mucor mould/ fungi which is commonly found in soil, plants, manure, and decaying fruits and vegetables. These Fungi belonging to the class Zygomycetes and order Mucorales often cause devastating angio-invasive infections, primarily in co-morbid and immunocompromised patients. The emergence of mucormycosis is being reported globally. In India, people with diabetes mellitus are highly susceptible to the disease. But during the second wave of Covid-19 in India, several cases of mucormycosis, also called the "black fungus" disease, have been reported among convalescing and convalescent COVID-19 patients across India with a mortality rate of 50%. More than 5000 cases of mucormycosis during the second wave of Covid-19, have been reported in about 21 states of the country, with Maharashtra and Gujarat states reporting highest number of cases (as on 21 May 2021). The infection has claimed over 120 lives so far, and has complicated recovery from Covid-19 in many more. The Indian Union health ministry has declared mucormycosis as a notified disease under the Epidemic Diseases Act, 1897.
ABSTRACT
Since the identification of the SARS-CoV-2, genus Beta-Coronavirus, in January 2020, the virus quickly spread in less than 3 months to all continents with a susceptible human population of about a 7.9billion, and still in active circulation. In the process, it has accumulated mutations leading to genetic diversity. Regular emergence of variants of concern/significance in different ecology shows genetic heterogeneity in the base population of SARS-CoV-2 that is continuously expanding with the passage of the virus in the vast susceptible human population. Natural selection of mutant occurs frequently in a positive sense (+) single-stranded (ss) RNA virus upon replication in the host. The Pressure of sub-optimal levels of virus-neutralizing antibodies and also innate immunity influence the process of genetic/ antigenic selection. The fittest of the mutants, that could be more than one, propagate and emerge as variants. The existence of different lineages, clades, and strains, as well as genetic heterogeneity of plaque purified virus population, justifies SARS-CoV-2 as 'Quasispecies‘ that refers to swarms of mutant sequences generated during replication of the viral genome, and all mutant sequences may not lead to virion. Viruses having a quasispecies nature may end up with progressive antigenic changes leading to antigenic plurality that is driven by ecology, and this phenomenon challenges vaccination-based control programs. © 2021, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved.