Chapter 2: Coronaviruses: Animals as source of transmitting agent

Abstract

The SARS-CoV-2-infected disease (COVID-19) outbreak is the latest highly transmissible and pathogenic disease caused by a coronavirus. The coronavirus belong to a group of viruses that are known to infect human including 229E (alpha coronavirus), NL63 (alpha coronavirus), OC43 (beta coronavirus), HKU1 (beta coronavirus), MERS-CoV (causes Middle East Respiratory Syndrome, MERS), SARS-CoV (causes Severe Acute Respiratory Syndrome, SARS). This chapter discusses the various aspects of the disease including genome organization, its link to bat distribution, virulence ability and factors that suggest such emerging disease. Genome analysis revealed the SARS-CoV-2 is linked to bat CoV virus which indicate bat being the primary reservoir and evolution of human infecting virus is highly influenced by the global distribution of bats. However, there is no concrete evidence confirming direct transmission of bat virus to human. In CoVs, rapid evolution is commonly through frequent recombination of their genomes upon infecting the same host cell and if involves the nucleotide binding domain (NBD) of spike gene, this can contribute to the virus ability to adapt to different hosts and causing the ‘jumping species’ to occur. External factors also were hypothesized to influence greatly in several emerging new pathogenic viruses. Anthropological activity such as deforestation and global wildlife trade which allow direct and indirect contact of wildlife and human drove fast emergence of new pathogenic viruses and zoonotic disease proliferation. Without collaboration and coordination for all involved parties globally, efforts to educate and curb the occurrence of new pandemics will be in futile.