A year on from the first reported human case of infection with Middle East respiratory syndrome coronavirus (MERS-CoV), the world still has few answers to the most pressing question from a public-health perspective: what is the source of the steady stream of new cases? Only with this information can the outbreak be controlled.
There have so far been 114 confirmed cases of MERS-CoV infection, including 54 deaths, with another 34 suspected cases (see ‘Catching on’). All originated in the Arabian Peninsula, with most in Saudi Arabia and others in Jordan, Qatar and the United Arab Emirates (UAE). Imported cases have occurred in the United Kingdom, France, Italy and Tunisia. The virus is thought to be an animal virus that sporadically jumps to people — there are no signs yet that it can spread easily between humans, although limited spread between people in close contact has been seen.
But a lack of epidemiological studies means that the source of the virus is still unknown. This is “absolutely unacceptable”, says Michael Osterholm, head of the University of Minnesota’s Center for Infectious Disease Research and Policy in Minneapolis. Affected countries have to some extent lacked a sense of urgency, agrees Jean-Claude Manuguerra, head of the Laboratory for Urgent Response to Biological Threats at the Pasteur Institute in Paris. They have also tended to consider it a sovereign issue that is the business of national authorities, not outsiders, he adds.