Two human coronavirus species were known to infect human from the 1960s onward. These wee known as HCoV-229E and HCoV-OC43. In 2003 SARS-CoV was identified as causing an aggressive lung disease. Fortunately, this virus did not spread within the human population. However it became clear that the human coronavirus group could contain more members then previously assumed.
In January 2003, a 7-month-old child appeared in an Amsterdam hospital with quite severe respiratory disease. Chest radiography showed typical features of bronchiolitis. A nasal swab was collected 5 days after the onset of disease. This was tested and from this sample the complete genome of a “novel” virus was found, which was named at that time HCoV- NL63. HCoV-NL63 forms a subcluster with the previously described HCoV-229E.
A second research group in the Netherlands described essentially the same virus shortly after the first publication on HCoV-NL63. Fouchier described a virus (which they named HCoV-NL) in a Vero-E6 cell culture supernatant (Fouchier et al., 2004). A nose swab sample was collected from an 8-month-old boy suffering from pneumonia in 1988. Virus from that sample was also cultivated first on tMK cells and subsequently passaged onto Vero cells. The similarity with the previously described HCoV-NL63 strain was very high (98.8% at the nucleotide level) and it can be concluded that these two virus isolates represent the same species. Most differences between the two virus variants are clustered in the amino terminal region of the spike protein.
Almost 1 year later, a third group described the same human coronavirus (Esper et al., 2005b). Using universal coronavirus primers, patient samples were identified with coronaviruses that did not match at the nucleotide level with HCoV-229E, HCoV-OC43 or SARS-CoV. These authors gave their virus the name ‘New Haven coronavirus’ (HCoV-NH), although the partial sequences oftheir isolates clearly show that the novel coronaviruses identified in New Haven, CT, USA, are very similar to the isolates from the Netherlands (94–100% identical at nucleotide level) and thus represent the same species (van der Hoek & Berkhout, 2005). Careful reading of the early coronavirus literature indicates that HCoV-NL63, or the novel group II virus HCoV- HKU1, may have been observed previously.
The first two studies on HCoV-NL63 clearly indicated that infection by this virus is not a rare event (Fouchier et al., 2004; van der Hoek et al., 2004). Both reports presented several HCoV-NL63 infected patients that suffered from upper or lower respiratory tract illnesses. Since then a number of reports have shown that the virus is not unique to the Netherlands, and that it can be found worldwide. In Australia, HCoV-NL63 could be detected in 16 of 766 patients with acute respiratory disease (2.1%; Arden et al., 2005). A Japanese study on 118 children under the age of 2 that suffered from bronchiolitis and who were admitted to the hospital revealed three positive patients (2.5%; Ebihara et al., 2005a), and a second Japanese study presented five HCoV-NL63 infections among 419 specimens collected from children with respiratory infections (1.2%) (Suzuki et al., 2005). Among 279 hospitalized children with upper and lower respiratory tract illness in Belgium, seven children were identified with HCoV-NL63 (2.3%) (Moes et al., 2005). In France, 28 of 300 patients with upper and lower respiratory tract illness under the age of 20 harboured HCoV-NL63 RNA (9.3%) (Vabret
(Van Der Hoek, Pyrc, and Berkhout 2006)
(Dijkman and Hoek 2009)
Dijkman, Ronald, and Lia van der Hoek. 2009. “Human Coronaviruses 229E and NL63 :” Journal of the Formos Medical Association 108 (4): 270–79. http://dx.doi.org/10.1016/S0929-6646(09)60066-8.
Van Der Hoek, Lia, Krzysztof Pyrc, and Ben Berkhout. 2006. “Human coronavirus NL63, a new respiratory virus.” FEMS Microbiology Reviews 30 (5): 760–73. doi:10.1111/j.1574-6976.2006.00032.x.