Rewiev of some important characteristics of human coronaviruses

Coronaviruses are group of enveloped, sense-positive, single-stranded RNA viruses with large genome (ranges from 27 to 34 kbp), members of the family Coronaviridae. Size of the viruses is very variable, in average 120 nm in diameter (vary between 50 and 200 nm). Corona viruses commonly caused infections of the respiratory tract in humans and birds, affecting other mammals with gastrointestinal clinical manifestations. Seven coronavirus species are known to cause human disease. Four of them typically cause common cold symptoms in immunocompetent individuals. Тhe tree other strains (SARS-CoV, MERS-CoV and SARS-CoV-2) are zoonotic in origin and have been linked to fatal illnesses. SARS-CoV (Severe acute respiratory syndrome coronavirus) was the causal agent of the Severe acute respiratory syndrome outbreaks (SARS) in 2001 and 2003 in Guangdong Province, China. MERS-CoV (Мiddle East respiratory syndrome coronavirus - MERS) was the pathogen responsible for Severe respiratory disease outbreaks in 2012 in the Middle East. SARS-CoV-2, novel coronavirus, caused current global pandemic of the respiratory disease COVID-19. High prevalence and wide distribution of coronaviruses, the large genetic diversity and frequent recombination of their genomes, and increasing human-animal interface activities, novel coronaviruses are likely to emerge periodically in humans owing to frequent cross-species infections and occasional epidemics including latest global ongoing pandemic. Key words: coronaviruses, SARS-CoV, MERS-CoV, SARS-CoV-2, COVID 1