The history of the emergence and transmission of human coronaviruses

Elijah N Mulabbi,Robert Tweyongyere,Denis K Byarugaba

doi:10.4102/ojvr.v87i1.1872

Elijah N Mulabbi, Robert Tweyongyere + Show 1 more

Open Access

https://doi.org/10.4102/ojvr.v87i1.1872

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Abstract

Human coronaviruses are known respiratory pathogens associated with a range of respiratory illnesses, and there are considerable morbidity and hospitalisation amongst immune-compromised individuals of all age groups. The emergence of a highly pathogenic human coronavirus in China in 2019 has confirmed the long-held opinion that these viruses are important emerging and re-emerging pathogens. In this review article, we trace the discovery and emergence of coronaviruses (CoVs) over time since they were first reported. The review article will enrich our understanding on the host range, diversity and evolution, transmission of human CoVs and the threat posed by these viruses circulating in animal populations but overtime have spilled over to humans because of the increased proximity between humans and animals.

Highlights

Coronaviruses (CoVs) are positive-sense, single-stranded ribonucleic acid (RNA) viruses with a linear, non-segmented viral genome
The sub-family Coronavirinae is divided into four genera: the alpha; beta; gamma and deltacoronaviruses (Zhang et al 2018)
The four human CoVs that are endemic in human populations and cause self-limiting common cold (HCoV 229E, HKU1, NL63 and OC43) are droplet-transmitted; these viruscontaining droplets are released to the environment when an infected person breathes, coughs, sneezes or talks

Summary

Introduction

Coronaviruses (CoVs) are positive-sense, single-stranded ribonucleic acid (RNA) viruses with a linear, non-segmented viral genome. Just 7 years after the discovery of MERS-CoV, in December 2019, a novel human CoV that is similar to SARS-CoV was discovered and isolated from patients in the Hubei Province, China, suffering from pneumonia, but has since spread to many countries across all continents (Zhu et al 2020) This novel virus causes coronavirus disease (COVID-19), which has been declared a pandemic by the World Health Organisation (Summers et al 2020). The four human CoVs that are endemic in human populations and cause self-limiting common cold (HCoV 229E, HKU1, NL63 and OC43) are droplet-transmitted; these viruscontaining droplets are released to the environment when an infected person breathes, coughs, sneezes or talks This efficient human-to-human transmission of these virus is sustainable because these viruses replicate mainly in the central and upper parts of the respiratory tract (Perlman & Netland 2009; Richard et al 2017; Wege & Ter Meulen 1982). There are more studies being done, which will improve our understanding on the human-to-human transmission dynamics of SARS-CoV-2

Conclusion

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