10 years ago it was SARS, now the new coronavirus worrying pandemic planners is theMERS (Middle Eastern Respiratory Syndrome) coronavirus, that emerged in Saudi Arabia, last year. The number of cases is gathering momentum and we don’t yet know how it is transmitted or what animal is harbouring it. As Saudi Arabia is the host for the annual Hajj pilgrimage one of the largest mass gatherings in the world, it is important we find out before millions of visitors descend on the country.
Timeline and geography of the epidemic
The virus has been in circulation since April 2012 and for a year caused a steady trickle of cases with a fatality rate of around 60% in cases. This April and May the incidence jumped to 19 cases each month, a cluster of cases was identified and limited transmission between people was demonstrated. The virus has spread within families and from patients to the health care workers caring for them. However it is not as dangerous to health care workers as SARS was, according to WHO. People with the disease have travelled with it to several countries in Europe but the infection does not seem to have established in those countries.
WHO reports ”September 2012 to date, WHO has been informed of a total of 61 laboratory-confirmed cases of infection with MERS-CoV, including 34 deaths. The cases have come from Jordan, Qatar, Saudi Arabia, and the United Arab Emirates (UAE). France, Germany, Italy, Tunisia and the United Kingdom also reported laboratory-confirmed cases; they were either transferred there for care of the disease or returned from the Middle East and subsequently became ill.”
WHO requires that cases (case definition) are notified and urges all countries to survey for cases of severe acute respiratory infections ( fever cough breathing difficulty), take samples and isolate patients.
What is the animal source?
Like more than 60% of emerging human diseases expert think the virus comes from an animal source but which animal? SARS came to man through jumping between two hosts: bats and civet cats. The RNA sequence of this new virus suggests it is most similar to coronaviruses from bats and suggests them as the ultimate source (2,3)
Anna Petherick in the Lancet this week (4) suggests that the coronavirus went from bats to an intermediate host before jumping to man in a similar pattern to the movement of SARS between species. To find out what is going on, she says we need to use the several serological tests that have been developed, to monitor human and sentinel animal populations for the presence of this new virus. This kind of work could help clear up the issue of the animal host, the routes of transmission and whether a mild form of the disease exists.
Public health concern?
Saudi Arabia is the annual destination for 4 million pilgrims from over 180 countries each year as they complete the Hajj pilgrimage. This mass gathering has spread meningitis and flu in the past and now all pilgrims must have appropriate vaccinations to prevent epidemics.
The public health authorities closely monitored last year’s Hajj in for signs of the spread of the MERS virus. Pilgrims had high levels of respiratory symptoms but MERS coronavirus was not detected by PCR in any (5).
With increased numbers of cases and limited human transmission, public health measures may need to be put in place before this year’s pilgrimage begins. So far there is no advice not to travel but the Saudi Arabian embassy advises elderly, pregnant and terminally ill patients and children not to travel.
Have we moved on from SARS? Are we better prepared?
Global disease surveillance has moved on since 2002. The SARS along with threats of flu pandemics pushed the world into revising the international health regulations in 2007 for the first time since 1969 to take such global events into account and enable a better response. The regulations require countries maintain a core of public health surveillance and response capacity and “notify all events that may constitute a public health emergency of international concern within 24 hours of assessment.” And they allow for international disease control efforts including screening of travellers to prevent disease spread. Collective action and collective responsibility are underlined.
As part of the collective effort, WHO and the CDC have developed surveillance networks and have taken on board the need to monitor animal (and plant) populations in a ‘one health’ approach. And as many of these diseases appear to emerge in developing countries USAID has stepped in with its Emerging Pandemic Threats Program. So we may be better prepared now. However a recent article in Emerging Infectious Diseases warns against complacency: “Of 194 World Health Organization member states that signed on to the International Health Regulations (2005), <20% had achieved compliance with the core capacities required by the deadline in June 2012.” (6)
Unfortunately there is a problem that is impeding potential research into the MERS virus and the effort to control it. The virus is the subject of a patent application by the Dutch research group that discovered it. If a patent was granted it would affect the conditions under which researchers can use samples of the virus and serological tests for it that have been developed. The Saudi researchers have complained about this. The International Health Regulations have no rules to deal with this issue.(7)
Dr Margaret Chan underlined the threat to the world at the World Health Assembly and the need to cooperate: “The novel coronavirus is not a problem that any single affected country can keep to itself or manage all by itself. The novel coronavirus is a threat to the entire world.”
Journal articles about MERS
2. Genomic Characterization of a Newly Discovered Coronavirus Associated with Acute Respiratory Distress Syndrome in Humans.Sander van Boheemena, Miranda de Graafa, Chris Lauberb, Theo M. Bestebroera, V. Stalin Raja, Ali Moh Zakic, Albert D. M. E. Osterhausa, Bart L. Haagmansa, Alexander E. Gorbalenyabd, Eric J. Snijderb, and Ron A. M. Fouchiera. mBio volume 3 Number 6 e00473-12
3. Human Betacoronavirus 2c EMC/2012–related Viruses in Bats, Ghana and Europe.Annan A, Baldwin HJ, Corman VM, Klose SM, Owusu M, Nkrumah EE, et al. Emerging Infectious Diseases [Internet]. 2013 Mar. http://dx.doi.org/10.3201/eid1903.121503
4. MERS-CoV: in search of answers. Petherick, A. The Lancet, Volume 381, Issue 9883, Page 2069, 15 June 2013 doi:10.1016/S0140-6736(13)61228-3
5. Emerging respiratory and novel coronavirus 2012 infections and mass gatherings. J.A. Al-Tawfiq, C.A.H. Smallwood, K.G. Arbuthnott, M.S.K. Malik, M. Barbeschi and Z.A. Memish. Eastern Mediteranean Health Journal Vol.19 Supplement1 2013 p48.
6. Progress in global surveillance and response capacity 10 years after severe acute respiratory syndrome. Christopher R. Braden, Scott F. Dowell, Daniel B. Jernigan, and James M. Hughes Emerging Infectious Diseases Vol. 19, No. 6 864-869.
7. Who owns MERS. H5N1 blog. http://crofsblogs.typepad.com/h5n1/2013/06/who-owns-mers.html