Coronaviruses - important animals and human pathogens

This article aims at the presentation of most prominent infectious agents that emerged just few months age. Coronaviruses (CoVs) constitute a large group of ssRNA viruses that cause acute and chronic diseases in animals and humans. They show a high degree of genetic variability resulting in the existence of four major genera (alfa-, beta-, gamma– and deltacoronaviruses), that further diverge into multiple subgenera and genetic lineages. Different types of CoVs occur naturally in cattle, horses, pigs, cats, dogs, rodents and many species of birds. Bats however, are considered as the natural reservoir and primary source of novel coronaviruses with zoonotic potential, including MERS-CoV, SARS-CoV-1 and SARS-CoV-2. There is evidence that intermediate hosts (e.g. civets, dromedary camels, pangolins), can play a key role in the transmission of coronaviruses from bats to humans. Currently, the major concern is associated with SARS-CoV-2, a causative agent of COVID-19 – a human disease that originated in China in late 2019 and spread globally in the early 2020. It has been shown recently, that SARS-CoV-2 is capable of infecting some species of animals, including cats, tigers, ferrets and minks. These rare cases have most likely been caused by human-to-animal transmission and further extensive research are required to elucidate the role of animals in the epidemiology of COVID-19

Animal coronaviruses in the light of COVID-19

Coronaviruses are extremely susceptible to genetic changes due to the characteristic features of the genome structure, life cycle and environmental pressure. Their remarkable variability means that they can infect many different species of animals and cause different disease symptoms. Moreover, in some situations, coronaviruses might be transmitted across species. Although they are commonly found in farm, companion and wild animals, causing clinical and sometimes serious signs resulting in significant economic losses, not all of them have been classified by the World Organization for Animal Health (OIE) as hazardous and included on the list of notifiable diseases. Currently, only three diseases caused by coronaviruses are on the OIE list of notifiable terrestrial and aquatic animal diseases. However, none of these three entails any administrative measures. The emergence of the SARS-CoV-2 infections that have caused the COVID-19 pandemic in humans has proved that the occurrence and variability of coronaviruses is highly underestimated in the animal reservoir and reminded us of the critical importance of the One Health approach. Therefore, domestic and wild animals should be intensively monitored, both to broaden our knowledge of the viruses circulating among them and to understand the mechanisms of the emergence of viruses of relevance to animal and human health