Coronavirus Disease 2019 – COVID-19

Abstract

In the past decades, several new diseases have emerged in new geographical areas, with pathogens including Ebola, Zika, Nipah, and coronaviruses (CoV). Recently, a new type of viral infection has emerged in Wuhan City, China, and initial genomic sequencing data of this virus does not match with previously sequenced CoVs, suggesting a novel CoV strain (2019-nCoV), which has now been termed as severe acute respiratory syndrome CoV-2 (SARS-CoV-2). Although CoV disease 2019 (COVID-19) is suspected to originate from an animal host (zoonotic origin) followed by human-to-human transmission, the possibility of other routes such as food-borne transmission should not be ruled out. Compared to diseases caused by previously known human CoVs, COVID-19 shows a less severe pathogenesis but higher transmission competence, as is evident from the continuously increasing number of confirmed cases. Compared to other emerging viruses such as Ebola virus, avian H7N9, SARS-CoV, or MERS-CoV, SARS-CoV-2 has shown relatively low pathogenicity and moderate transmissibility Codon usage studies suggest that this novel virus may have been transferred from an animal source such as bats. Early diagnosis by real-time PCR and next-generation sequencing has facilitated the identification of the pathogen at an early stage. Since no antiviral drug or vaccine exists to treat or prevent SARS-CoV-2, potential therapeutic strategies that are currently being evaluated predominantly stem from previous experience with treating SARS-CoV, MERS-CoV, and other emerging viral diseases. In this review, we address epidemiological, diagnostic, clinical, and therapeutic aspects, including perspectives of vaccines and preventive measures that have already been globally recommended.

COVID-19, an Emerging Coronavirus Infection: Current Scenario and Recent Developments – An Overview

“…Recently, few of the reports have highlighted the role of animals, veterinary, crossspecies jumping, zoonotic links and spillover events of SARS-CoV-2 and its transmission to humans, before acquiring human to human transmission, as have been implicated with SARS and MERS 2,6,[40][41][42][43][44][45][46] . Atypical exposure point of SARS-CoV-2 has pointed out towards the implication of seafood market in Wuhan, China 47 , as a wet-market that sells different kinds of poultry, bats, snakes, marmots and other wildlife animals for human consumption at a single place, that can act as hot spot acting as a human-animal interphase/ interaction event, where zoonotic viruses can jump to cross-species barrier-or spillover to humans through seafood tanks, presence of live-dead animals body fluids, blood, excretion or air born mode of transmission leading to the emergence of novel pathogens such as SARS-COV-2 and others 48 .…”

“…As bats are employed as materia medica, so we can not deny the probability of zoonotic spillover through bats 24,28 . By involving intermediate hosts (bridge hosts), SARS-CoV-2/ 2019-nCoV attained altered pathogenicity and enhanced transmissibility through modified receptor binding domain (RBD) 2,18,26,[49][50][51][52][53][54][55][56][57] .…”

“…Nevertheless, multiple drugs are under study, including other antiretrovirals, such as is the case of remdesevir, but also antivirals such as oseltamivir and other therapies, including chloroquine and even indomethacin. Researchers are making high efforts to design and develop suitable vaccines for COVID-19, which may take some time 2,[67][68][69] . In this context, efficient management of COVID-19 pneumonia by active prevention and control in a scientific manner is of utmost importance following the national and international developed guidelines 70 .…”

“…Indeed, considering previous experiences of edidemics and pandemics in different regions of the world, with other emerging infectious diseases, as the case of SARS, MERS 16,27 , but also swine flu and avian flu, Ebola, Nipah, Chikungunya and Zika 2,[67][68][69][89][90][91] , health authorities and healthcare providers including hospitals must apply the learned experiences on previous epidemics and pandemics to frame some implementable protective strategies 14,16,[92][93][94][95] . That includes the rational use of quarantine and appropriate disease prevention, management and control procedures to be timely implemented 15,19,70,96 .…”

“…Coronaviruses are continually evolving. Examples include the Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS) that caused fatal outbreaks earlier, and now the present emerging Coronavirus Diseases 2019 (COVID- 19), caused by the SARS-2 Coronavirus (SARS-CoV-2), initially expressed as pneumonia of unknown origin, thus posing a significant threat to public health across the globe [1][2][3] . COVID-19 has represented a high negative impact on the economy of China as well as a few other nations 4,5 .…”