Understanding Human Coronavirus HCoV-NL63

Abdul-Rasool, Sahar; Fielding, Burtram C

Five human coronaviruses have been identified to date, four of which are known to continuously circulate in the human population, especially in young children [8, 9] . HCoV-OC43 and HCoV-229E, first identified in the mid-1960s [10, 11] , were shown to cause the common cold [12] , but rarely infections of the lower respiratory tract [3] . A third human coronavirus, which causes severe acute respiratory syndrome, SARS-CoV, was identified in 2003 [13, 14] . This virus had a worldwide spread, causing acute respiratory illness with a mortality rate of ~10% [15] . The last reported SARS-CoV infections were laboratory acquired in 2004, and the virus has not been detected in the human population since [16, 17] . More recently, two additional human coronaviruses were identified; HCoV-HKU1 was isolated from a 71-year-old man who presented with fever and cough [3] , and HCoV-NL63 isolated from a seven-month-old baby [2] . The latter is the topic of this review.