Novel Coronavirus in UK and Saudi Arabia
By Amesh A. Adalja, MD, FACP, October 5, 2012
Since the deadly outbreak of SARS and the discovery of its etiological agent, the SARS Coronavirus (SARS-CoV), there has been a heightened awareness that coronaviruses cause severe transmissible disease, a far cry from the common cold they were exclusively linked to in the past. From 2003 to 2011, 2 new human coronaviruses have been discovered, both of which caused mild illness.1 However, in 2012, a third new human coronavirus (HCoV) was discovered and was sequenced at Erasmus Medical Center (EMC) in the Netherlands. The new virus, designated HCoV-EMC, is responsible for 2 severe cases in England and Saudi Arabia, 1 of which was fatal.2
Genus Coronaviruses that Infect Humans
The Coronavirus genus contains several viruses that are known to infect humans. The first human coronavirus, HCoV-229E, was isolated in 1965, followed soon after by the isolation of HCoV-OC43. The eventual discovery of other coronaviruses that infect other animal species led to the division of the animal and human coronavirus into 3 groups (1-3). These groups have subsequently been split into subgroups.1 HCoV-EMC is in the 2c group, where it clusters with 2 coronaviruses of bats. The classification of human coronaviruses is summarized below.1,2
Table 1: Human Coronaviruses
Thus far, 2 cases of HCoV-EMC infection have been confirmed. The first case, which was fatal, occurred in June in a 60-year-old man in Saudi Arabia; the second case occurred in a 49-year-old Qatari man who traveled to Saudi Arabia and is currently being treated in England. From early case descriptions, it appears pneumonia is the primary manifestation of the disease. The WHO has published a case definition (Figure 1). It appears that the disease has an incubation period of up to 10 days and that it is not easily transmitted between humans, although full airborne isolation is recommended. As with all coronaviruses, no specific treatment is available.2
Figure 1: WHO Case Definition for People to Be Investigated for Infection3
Confirmatory testing is via nucleic acid amplification, which is available at reference labs; standard coronavirus primers may be able to detect the virus. Samples are to be handled in a BSL-3 setting.
Many Questions Remain
The detection of the new coronavirus raises many questions that will likely be answered in the months to come, including:
Are there asymptomatic cases? Will serosurveys be performed?
Given that human-to-human transmission appears difficult for the virus, what is the common exposure between the 2 cases? Is it animal related?
As with SARS, does the possibility exist of superspreaders who are able to transmit the virus between humans?
Are there prior unexplained cases that can be attributed to this virus?
McIntosh K, Perlman S. Coronaviruses, including Severe Acute Respiratory Syndrome (SARS)-associated coronavirus. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Churchill Livingstone; 2010.
UK Health Protection Agency. Novel coronavirus, 2012. http://www.hpa.org.uk/webw/HPAweb&Page&HPAwebAutoListName/Page/1317136202637. Accessed October 2, 2012.
World Health Organization. Revised interim case definition—novel coronavirus. http://www.who.int/csr/disease/coronavirus_infections/case_definition/en/index.html. Accessed October 2, 2012.