ABSTRACT
Foot-and-mouth disease (FMD) and Coronavirus Disease 2019 (COVID-19) are transboundary diseases caused by single-stranded positive-sense RNA viruses with similarities in genome replication and viral protein synthesis. In FMD, asymptomatic infection leads to carrier status and persistently infected animals that threaten the animals vaccinated with a trivalent inactivated whole virus vaccine. Similar information on COVID-19 is not yet available. As COVID-19 vaccination is introduced in January 2021 (since 16 January 2021 in India), its outcome can be assessed by the year-end;and while doing so, the experiences gained in the control of FMD in livestock worldwide can be applied, including monitoring of vaccination response, duration of immunity, level of herd immunity developed, and antigenic matching of the vaccine virus. Antigenic divergence of the virus is a major issue in FMD, and different geographical regions in the world use different virus strains in vaccine preparations to antigenically match circulating virus strains in respective regions for control of the disease. Non-synonymous mutations in the critical antigenic determinants of SARS-CoV-2 have been observed, and there is likely the existence/development of antigenic variants. Therefore, during the post-COVID-19 vaccination regime, it will be essential to monitor the suitability of the in-use vaccine strain region-wise from time to time, as there could be an eruption of isolated outbreaks in a country arising due to antigenic variation and variants. In the context of the present scenario of COVID-19 around the Globe and multiple ongoing efforts to develop suitable vaccine(s) to control the disease, it is a must to develop NSP-antibody (that differentiate infected from vaccinated) assays to differentiate infected from vaccinated individuals(DIVI;DIVA in veterinary epidemiology). The techniques used and experiences gained in ongoing FMD control programs in the endemic countries can be applied to COVID-19 control in a country;and finally, the Globe. After achieving the control of COVID-19, the aim would be to eradicate the virus, which will be tough even with vaccination, as the disease/infection may become endemic during the time to come. To achieve this, applying the principles of Progressive Control Pathway for Foot-and-Mouth Disease (PCP-FMD;FAO/OIE) to COVID-19 control will be beneficial in its control. The present review discusses the issue of control of COVID-19. © 2021 by the authors.
ABSTRACT
Severe acute respiratory syndrome (SARS)-coronavirus-2 (CoV-2) is a beta-coronavirus (beta-CoV;sarbecovirus), like its predecessors SARS and MERS CoVs. Of the structural proteins of the virus, the Spike (S) protein on the virion envelope binds to the host cell ACE2 through viral epitopes in the receptor-binding domain (RBD). Deletions in the ORF8 as well as mutations in the S gene of SARS-CoV of 2003 were related to adaptation of the virus to humans. The emergence of novel variants of SARS-CoV-2, viz., B.1.1.7, B.1.427 and B.1.429, B.1.617 and its Kappa and Delta strains/ variants, B.1.351, and P.1 in the United Kingdom, Americas, India, South Africa and Brazil, respectively, has been found be associated with the current waves of the COVID-19 pandemic. These variants are antigenically dissimilar, whereas the current COVID-19 vaccines are monovalent. This is a handicap in the control program. The Delta variant has been reported in 74 countries as of 14 June 2021 and the anticipated third wave involving this variant is of concern to the countries (www.gavi.org). Of late, on 17 June 2021, Delta Plus variant was identified in India (AIIMS, Bhopal, India). Circulation of virus in vaccinated population may lead to endemicity, and this can be monitored by regular serosurveillance for antibodies against select non-structural proteins (NSPs) of the virus;antibodies to NSPs will indicate virus replication in the host. Endemic areas will have higher NSP reactors. It is predicted that the Delta B.1 variant may ignite the third wave of the disease in many countries. As it has been difficult to achieve uniformity in time and density of the vaccination even in the districts, circulation of the virus in partially immune population may lead to the selection of newer variants of SARS-CoV-2. The presence of monoclonal antibody resistant mutants and neutralization—escape mutants in quasispecies structure of another + sense RNA virus, i.e., Aphthovirus (FMD virus;foot and mouth disease virus) in the family Picornaviridae is well documented. The situation could be similar in the Coronaviridae member SARS-CoV-2. Previous immunity may not protect against current/ future mutants thereby pro-longing the COVID-19 control Programme. © 2022 Sharanagouda S. Patil et al.
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.
ABSTRACT
Coronaviruses (CoVs), classified into four genera, viz., alpha-, beta-, gamma-, and Delta-CoV, represent an important group of diverse transboundary pathogens that can infect a variety of mammalian and avian species including humans, animals, poultry, and non-poultry birds. CoVs primarily infect lung and gut epithelial cells, besides monocytes and macrophages. CoVs have high mutation rates causing changes in host specificity, tissue tropism, and mode of virus excretion and transmissions. The recent CoV zoonoses are SARS, MERS, and COVID-19 that are caused by the transmission of beta-CoVs of bats to humans. Recently, reverse zoonoses of the COVID-19 virus have been detected in dogs, tigers, and minks. Beta-CoV strains also infect bovine (BCoV) and canine species (CRCoV);both these beta-CoVs might have originated from a common ancestor. Despite the high genetic similarity between BCoV, CRCoV, and HCoV-OC43, these differ in species specificity. Alpha-CoV strains infect canine (CCoV), feline (FIPV), swine (TGEV and PEDV), and humans (HCoV229E and NL63). Six coronavirus species are known to infect and cause disease in pigs, seven in human beings, and two in dogs. The high mutation rate in CoVs is attributed to error-prone 3′-5′ exoribonuclease (NSP 14), and genetic recombination to template shift by the polymerase. The present compilation describes the important features of the CoVs and diseases caused in humans, animals, and birds that are essential in surveillance of diverse pool of CoVs circulating in nature, and monitoring interspecies transmission, zoonoses, and reverse zoonoses. © 2021, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved.