MERS-CoV: in search of answers

Abstract

Middle East Respiratory Syndrome coronavirus (MERS-CoV) has been a cause for concern for months, with a steady trickle of new cases, often fatal, dating back to April, 2012. Until March of this year there were fewer than fi ve confi rmed infections per month, but April and May each saw 19 new cases, driven up by a cluster in the Al-Ahsa region in eastern Saudi Arabia. Most people now known to have caught MERS-CoV have done so from another human being. Eff orts to understand the infection have consequently been stepped up. A WHO team of experts tasked with trawling through the existing Saudi data has just returned from the country. It hopes to publish a report this month. Saudi Arabia’s Ministry of Health has also agreed to send samples from animals that seem likely candidates to harbour the virus to the USA for analysis. This marks a positive shift in tone: last autumn, the same ministry stood accused of ordering the sacking of Ali Mohamed Zaki, the virologist who alerted the medical community to this new threat by posting an entry on proMED (an infectious disease news website), and who sent a sample abroad to fi nd out what it could be. The little acts of diplomatic progress of late could have a substantive public health benefi t, by enabling researchers to answer the most important question about this virus: what non-human source acts as a conduit from which MERS-CoV can infect people? “It could be a food, an animal, or a contaminated product with virus on it from contact with an animal”, suggests Tony Mount, WHO’s technical lead on this virus. “If we can stop that, if we can somehow manage to interrupt that transmission, then the outbreaks won’t happen.” A close genetic relative of coronaviruses carried by pipistrelle bats, MERS-CoV is thought to have jumped from bats to something else, and from that something else to humans, repeating a pattern shared by other novel human viruses. The severe acute respiratory syndrome (SARS) pandemic of 2003 arose when a coronavirus hopped from bats to civet cats to people. And Nipah virus, which has caused many deaths in Bangladesh over the past 2 years, moved from bats to humans via date palm sap, a popular local drink.