Searching for the Animal Reservoir(s) of MERS-CoV

The World Organisation for Animal Health (OIE), organized in the 1920s, is an international organization of member countries established to promote global transparency of animal diseases, to collect scientific information relating to international animal disease control, and to develop standards for international trade of animals and animal products. The OIE is also tasked with disseminating information about emerging zoonotic diseases that have the potential for transmission to humans.

Recently, the OIE provided a summary of its current understanding of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in Update August 2014 - Questions & Answers on Middle East Respiratory Syndrome Coronavirus (MERS-CoV). This update provides general information about the MERS-CoV, but also has a detailed discussion about potential animal reservoirs for this coronavirus.

Several patterns or mode of human transmission of MERS have been identified by the World Health Organization. Human MERS infections can be transmitted in hospital settings and through close human to human contact. Both of these transmission settings require an infected individual. It is uncertain how the initial MERS cases in these situations became infected. These sporadic or community acquired infections could result from an environmental source or direct or indirect contact with animals.

The OIE points out that there is strong evidence that camels may be an animal host for this coronavirus, but perhaps not the only host. A number of confirmed MERS human cases had contact with camel or exposure to camels or camel products prior to infection. But not all sporadic MERS cases can be linked to camel or camel product exposure. The OIE specifically states “there remains the possibility that other animal species may be involved in the maintenance and transmission of the MERS-CoV”. The OIE concludes that more scientific research is necessary to determine whether other animal species, besides camels, may represent primary or intermediate hosts for MERS-CoV.

It Is Not Too Soon to Develop a MERS Vaccine

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is spreading throughout Saudi Arabia. The first known human infections of MERS-CoV occurred in 2012 in Jordan in a hospital setting.[1] Since then, more than 130+ suspected and confirmed cases have been recorded from eight countries in Europe, Africa, and the Middle East. More than 100 cases (about 80% of all cases) have occurred in Saudi Arabia.  More concerning is that the number of cases is increasing rapidly in Saudi Arabia. In the last two weeks the Saudi Arabia Ministry of Health has reported about 25 new cases.[2]

Most of these new cases in Saudi Arabia appear to have been infected by human-to-human contact. It is time for public health officials to be proactive and support plans for developing a MERS-CoV vaccine. Spanish researchers have taken the first step and report that they are working towards developing a MERS-CoV candidate vaccine.[3] More MERS-CoV vaccine research is needed immediately, just in case.

[1] Novel coronavirus infections in Jordan, April 2012: epidemiological findings from a retrospective investigation

[2] Kingdom of Saudi Arabia Ministry of Health Media Statements

[3] Engineering a Replication-Competent, Propagation-Defective Middle East Respiratory Syndrome Coronavirus as a Vaccine Candidate

h/t Giuseppe Michieli