Coronaviruses: a review of their properties and diversity

ABSTRACT

Human coronaviruses, which hitherto were causative agents of mild respiratory diseases of man, have recently become one of the most important groups of pathogens of humans the world over. In less than two decades, three members of the group, severe acute respiratory syndrome (SARS) coronavirus (CoV), Middle East respiratory syndrome (MERS)-CoV, and SARS-COV-2, have emerged causing disease outbreaks that affected millions and claimed the lives of thousands of people. In 2017, another coronavirus, the swine acute diarrhea syndrome (SADS) coronavirus (SADS-CoV) emerged in animals killing over 24,000 piglets in China. Because of the medical and veterinary importance of coronaviruses, we carried out a review of available literature and summarized the current information on their properties and diversity. Coronaviruses are single-stranded RNA viruses with some unique characteristics such as the possession of a very large nucleic acid, high infidelity of the RNA-dependent polymerase, and high rate of mutation and recombination in the genome. They are susceptible to a number of physical agents and several chemical agents used for disinfection procedures in hospitals and laboratories. They exhibit considerable genetic and host diversity, causing diseases of gastrointestinal and respiratory system in a wide range of vertebrate hosts including humans. The high prevalence of coronaviruses in domestic and wild animals, especially bats and birds, and the propensity for their genomes to undergo mutation and recombination may lead to emergence of new coronaviruses that could pose a serious threat to human and animal health