Middle East Respiratory Syndrome (MERS-CoV) is a viral respiratory illness that was first reported in Saudi Arabia in 2012 and has since spread to several other countries. Most people infected with MERS-CoV developed severe acute respiratory illness, including fever, cough, and shortness of breath; many of them died. Severe acute respiratory syndrome (SARS-CoV), also a severe viral respiratory illness, was first reported in Asia in February 2003 and spread to dozens of countries before being contained. Since 2004, there have been no known SARS cases. Both MERS and SARS belong to a family of viruses called coronaviruses.
Why Is the Study of MERS and SARS a Priority for NIAID?
In 2003, a novel coronavirus emerged from China and swept across the globe, causing deadly illness. More than 8,000 people fell ill with severe acute respiratory syndrome (SARS), and 774 died. The SARS coronavirus drew the collective focus of researchers throughout the world, but the disease disappeared quickly. No cases of SARS have been reported since 2004. In 2012, a new coronavirus emerged, causing an illness similar to SARS. Again, researchers at NIAID and across the globe have initiated studies to understand the Middle East respiratory syndrome coronavirus (MERS-CoV)—and how to stop it.
How Is NIAID Addressing This Critical Topic?
Although a case of SARS has not been documented since 2004, NIAID continues to support more than a dozen research projects on this coronavirus throughout the United States, because the knowledge can be applied to other studies. Those studies include developing SARS treatments, a vaccine, and a better understanding of how the virus interacts with the immune system.
When MERS-CoV emerged in 2012, NIAID intramural and extramural scientists mobilized quickly to research the virus. Key areas of investigation include basic research on where MERS-CoV comes from and how it causes disease, the development of animal models to study the virus, and the development of treatments and vaccines.
To develop effective therapeutics and vaccines against MERS-CoV, scientists must first understand how the virus survives, infects, and causes disease in people. This knowledge is gained by first studying the virus in tissue culture and then developing animal models that mimic human disease. After studies showed that MERS-CoV does not cause disease in standard mice or hamsters, scientists at NIAID Rocky Mountain Laboratories (RML) took the unusual step of moving directly to developing a large-animal model because of the public health implications posed by MERS.
Coronaviruses evolve quickly and have a long history of shifting between animal species, leading scientists to explore where MERS-CoV comes from and how people become infected. Thus far, evidence suggests bats may be a reservoir of the virus and that camels may have a role as an intermediate host of MERS-CoV. In humans, epidemiological studies show that the virus can be transmitted from person to person but only between people in close contact with one another, such as family members or patients being treated in clinical settings. Recent outbreaks have been closely linked to hospital settings.
NIAID-funded researchers at the University of Washington are searching for MERS-CoV therapeutics by analyzing which human genes are significantly disrupted in the early and late stages of infection. This information will help scientists to predict which classes of drugs may be able to stop the virus or the genetic disruptions it causes during infection. Their findings, published in April 2013, show that SARS-CoV and MERS-CoV affect human cells differently. In general, MERS-CoV disrupts more genes more profoundly and at more time points after infection than SARS-CoV.