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 potential zoonotic coronaviruses (SARS-CoV, MERS-CoV, and SARS-CoV-2) are of global health concerns. Early diagnosis is the milestone in their mitigation, control, and eradication. Many diagnostic techniques are showing great success and have many advantages, such as the rapid turnover of the results, high accuracy, and high specificity and sensitivity. However, some of these techniques have several pitfalls if samples were not collected, processed, and transported in the standard ways and if these techniques were not practiced with extreme caution and precision. This may lead to false-negative/positive results. This may affect the downstream management of the affected cases. These techniques require regular fine-tuning, upgrading, and optimization. The continuous evolution of new strains and viruses belong to the coronaviruses is hampering the success of many classical techniques. There are urgent needs for next generations of coronaviruses diagnostic assays that overcome these pitfalls. This new generation of diagnostic tests should be able to do simultaneous, multiplex, and high-throughput detection of various coronavirus in one reaction. Furthermore, the development of novel assays and techniques that enable the in situ detection of the virus on the environmental samples, especially air, water, and surfaces, should be given considerable attention in the future. These approaches will have a substantial positive impact on the mitigation and eradication of coronaviruses, including the current SARS-CoV-2 pandemic.