A chronicle of SARS-CoV-2: Part-I - Epidemiology, diagnosis, prognosis, transmission and treatment

Abstract

In order to benefit the public, community workers and scientific community, we hereby present a chronicle of SARS-CoV-2 that leads to the unseen precedent of social distancing and lockdown owing to coronavirus disease (COVID-19). Information on this life-threatening pandemic of COVID-19 is sparse and discrete; and the urgency is such that the dissemination of information is increasing with numerous daily publications on the topic. Therefore, we developed a comprehensive review on various aspects of SARS-CoV-2 and COVID-19. We scientifically compiled published research, news, and reports from various sources to comprehend and summarize the information and findings on Coronaviruses. The review explicitly covers the aspects like genome and pedigree of SARS-CoV-2; epidemiology, prognosis, pathogenesis, symptoms and diagnosis of COVID-19 in order to catalog the right information on transmission route, and influence of environmental factors on virus transmissions, for the robust understanding of right strategical steps for proper COVID-19 management. We have explicitly highlighted several useful information and facts like: i) No established relationship between progression of SARS-CoV-2 with temperature, humidity and/or both, ii) The underlying mechanism of SARS-CoV-2 is not fully understood, iii) Respiratory droplet size determines drop and airborne-based transmission, iv) Prognosis of COVID-19 can be done by its effects on various body organs, v) Infection can be stopped by restricting the binding of S protein and AE2, vi) Hydroxychloroquine is believed to be better than chloroquine for COVID-19, vii) Ivermectin with Vero-hSLAM cells is able to reduce infection by ~5000 time within 2 days, and viii) Nafamostat mesylate can inhibit SARS-CoV-2 S protein-initiated membrane fusion. We have also suggested future research perspectives, challenges and scope.

Keywords: COVID-19; MERS-CoV; Pathogenesis; SARS-CoV; SARS-CoV-2; Transmission.

Graphical abstract

Fig. 1

(a) Naming of coronavirus with respect to taxonomy and disease caused [Modified from Gorbalenya et al., 2020 (Nature Microbiology)]; (b) Phylogenetic tree of SARS-like coronaviruses and (c) Open reading frame (ORF) SARS-like coronaviruses [Figure adopted from Li et al., 2020 (Pharmaceutical Analysis)].

Fig. 2

Cumulative variation in total and daily new COVID-19 a) Cases, and b) deaths in the world since December 31st and April, 30th 2020. [Data Source: ourworldindata.org].

Fig. 3

Distribution of COVID-19 Cases among active, recovered and deaths in a) the world; and b) top 25 infected countries (By 30th April 2020) [Data Source: worldometers.info].

Fig. 4

Schematic diagram of COVID-19 progression; (a) Interaction between spike (S) protein and receptor (ACE2), the encircled zone is the initiation point from where infection spreads in host [Modified from_ Liu et al., 2020b; Liu et al., 2020a]; (b) Schematic representation of progression of SARS-CoV-2 inside host body [Modified from Shi et al., 2020 (Cell Death & Differentiation)].

Fig. 5

a) Radial diagram illustrating the age correlation with morbidity and b) Pie diagram illustrating Case Fatality Rate (CFR) by age and underling health conditions due to COVID-19. [CFR is based on Actualización n° 67, 5th April 2020; COVID-19 in Denmark, 6th April 2020; Epidemia in Rome COVID-19, 6th April 2020; COVID-19 in Korea, 5th April 2020; Epidemiologische situatie COVID-19, 3rd April 2020; Surveillances, V., 2020].

Fig. 6

Transmission pathways of the COVID-19 and their intersections with various environment.