Human coronaviruses: Origin, host and receptor

Abstract

Coronavirus is a type of RNA-positive single-stranded virus with an envelope, and the spines on its surface derived its official name. Seven human coronaviruses 229E, OC43, SARS, NL63, HKU1, MERS, SARS-CoV-2 can cause both a mild cold and an epidemic of large-scale deaths and injuries. Although their clinical manifestations and many other pathogens that cause human colds are similar, studying the relationship between their evolutionary history and the receptors that infect the host can provide important insights into the natural history of human epidemics in the past and future. In this review, we describe the basic virology of these seven coronaviruses, their partial genome characteristics, and emphasize the function of receptors. We summarize the current understanding of these viruses and discuss the potential host of wild animals of these coronaviruses and the origin of zoonotic diseases.

Keywords: COVID-19; Emerging coronavirus; Host; Human coronavirus; Receptor; SARS-CoV-2.

Fig.. 1

According to the modification of genus of the virus of classification report of 10th ICTV, the coronavirus suborder divides into four-part: α coronavirus,β coronavirus,γ coronavirus,δ coronavirus. The first two only infect mammals, and the latter two mainly infect birds or a few mammals.

Fig. 2

It is the timeline of coronavirus that was first discovered in human history. The 229E was first founded in 1966, and it was the first invented coronavirus of which seven ones could infect people. Secondly is OC43, which was isolated from patients with cold. The next one is SARS, the outbreak of SARS was discovered in November 2002 and ended in 2003. In the same year, NL63 was detected using the VIDISCA and PCR method. In 2004, HKU1 was reported by HKU and named. Seven years later, an outbreak was founded in the Middle East, caused by a novel coronavirus named MERS-CoV. In 2018, researchers surprisingly analyzed nasal swabs from 301 pneumonia patients treated in a hospital in East Malaysia. It was found that eight patients, except for one child, were infected with the newly discovered coronavirus, which the researchers of the study named CCOV-HuPn-2018. In December 2019, a case of SARS-CoV-2 was reported in Asia. Nevertheless, there is also evidence in NEJM that revealed that the 2019-nCoV infection could be diagnosed in Germany and transmitted outside to Asia. The authentic original place of SARS-CoV-2 is still unknown.

Fig. 3

origins of human coronavirus. Severe acute respiratory syndrome coronavirus is a novel coronavirus related to bats with recombination. Before the SARS epidemic outbreak, the bats' virus infected civets and evolved to adapt to infect humans. The MERS-CoV could be originated from bats and spread to camels about 30 years ago and has been prevalent in dromedary camels. HCoV-NL63 and HCoV-229E, these two viruses do not cause severe respiratory damage and usually only bring a mild cold. The ancestor of both of them has been founded in African bats recently, and the camelids could be the intermediate host of HCoV-229E. Discovery revealed that the coronavirus genomes of Malayan pangolin have high sequence similarity to SARS-CoV-2. It means that Malayan pangolins could be thought to be the possible intermediate host. HCOV-OC43 and HCOV-HKU1 could be originated from rodents. Black arrows showed the direction of propagation. In this figure, humans are the ultimate hosts of transmission.