ARDS with MODS: Rule out HCoV-EMC

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Sunday, 23 December, 2012

For cases of acute respiratory distress syndrome (ARDS) and multiorgan dysfunction syndrome (MODS) with no cause identified, clinicians should think of excluding the newly discovered coronavirus, HCoV-EMC. Nine laboratory confirmed cases have now been identified since April 2012 in Jordon, Saudi Arabia and Quatar, and 5 died. The latest case was in October 2012, but retrospective testing diagnosed cases in April 2012. A case fatality ratio of >50% plus clustering of cases over time and geography makes this virus of significant concern. For an updated timeline of events see Dan Butler’s overview in Nature.

WHO has published a case definition to assist in identifying new cases:

  • A person with an acute respiratory infection, which may include fever (≥ 38°C , 100.4°F) and cough; AND
  • suspicion of pulmonary parenchymal disease (e.g. pneumonia or Acute Respiratory Distress Syndrome (ARDS)) based on clinical or radiological evidence of consolidation; AND
  • not already explained by any other infection or aetiology, including all clinically indicated tests for community-acquired pneumonia according to local management guidelines; AND
  • travel to or residence in an area where infection with novel coronavirus has recently been reported or where transmission could have occurred.

Comment: The last point should not be rigidly adhered to if new cases outside Saudi Arabia, Jordon and Quatar are to be detected.

Details on management of suspect cases are available at WHO Global Alert and Response (GAR): Revised interim case definition – novel coronavirus.

Real-time PCR and antibody tests for HCoV-EMC have already been developed (Muller et al 2012).

Concern about HCoV-EMC is high owing to its similarity to SARS-HCoV and the epidemic of Severe Acute Respiratory Syndrome that was fortunately eradicated in 2003 (Chan et al 2012). SARS spread to personnel caring for patients (about 30% of cases were health care personnel); HCoV-EMC has not been detected in any health staff.

Six species of coronaviruses infecting humans have now been identified. They occur in two of the three genera of coronaviruses. None have been found in Gammacoronavirus. Two species are in the Alphacoronavirus genus: HCoV-229E and HCoV-NL63. Three are in the Betacoronavirus genus: HCoV-OC43, HCoV-HKU1 (lineage A); SARS-HCoV (lineage B); HCoV-EMC (lineage C). HCoV-EMC is most closely related to two species of Betacoronavirus lineage C isolated from insectivorous bats (Zali et al 2012). Bats will once more be under the microscope as a reservoir for human pathogens! However, the link between HCoV-EMC and bats has not been established.

References
Chan JF, Li KS, To KK, Cheng VC, Chen H, Yuen KY. Is the discovery of the novel human betacoronavirus 2c EMC/2012 (HCoV-EMC) the beginning of another SARS-like pandemic? Journal of Infection 2012;65(6):477-489. doi: 10.1016/j.jinf.2012.10.002

Corman V, Muller M, Costabel U, Timm J, Binger T, Meyer B, Kreher P, Lattwein E, Eschbach-Bludau M, Nitsche A, Bleicker T, Landt O, Schweiger B, Drexler J, Osterhaus A, Haagmans B, Dittmer U, Bonin F, Wolff T, Drosten C. Assays for laboratory confirmation of novel human coronavirus (hCoV-EMC) infections. Euro Surveillance 2012;6:17(49). doi:pii: 20334

Zaki AM, Boheemen S, Bestebroer TM, Osterhaus ADME, Fouchier RAM. Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. New England Journal of Medicine 2012;367:1814-1820. DOI: 10.1056/NEJMoa1211721

Posted on 23 December 2012 by Rick Speare