Contagion

05.03.14

Is Middle East Respiratory Syndrome (MERS) the Next SARS?

The first U.S. case of MERS landed in Indiana—smack-dab in the heartland. Is it time to panic?

More than 7,000 miles: this is the linear distance from Riyadh, Saudi Arabia to Munster, Indiana, the location of the first American case of Middle East Respiratory Syndrome (MERS).

The carrier, a health care provider, flew from Riyadh to Chicago, by way of London, and then boarded a bus to Indiana. One of the initial challenges to the Centers for Disease Control (CDC) will be precisely tracing his journey and all individuals who may have been exposed to the virus. This is no simple task, but one that the CDC is somewhat familiar with. (You may recall that the CDC had to conduct the same surveillance for patients diagnosed with SARS several years ago.)

The virus, MERS-CoV, belongs to a family of coronaviruses (CoV) and causes a series of symptoms. It was originally reported in Saudi Arabia in April 2012. The CDC reports 401 laboratory-confirmed cases of MERS, with 93 deaths. This virus’ high mortality rate—nearly 25 percent—and limited treatment options make it especially concerning to public health officials.

MERS patients tend to harbor preexisting health conditions and are much more likely to succumb to a MERS-CoV infection than a patient with SARS-CoV infection.

MERS conjures frightening memories of the 2003 SARS outbreak that originated in Hong Kong. There are similarities: Both are zoonotic viruses—meaning the virus acquired a mutation to jump from an animal host reservoir to a human host. The animal reservoir for SARS is bats, whereas the reservoir for MERS is primarily camels. Both are severe respiratory illnesses and the majority of symptoms revolve around progressive difficulty with breathing, oxygenation, and systemic infection.

However, there are important differences. MERS patients tend to harbor preexisting health conditions and are much more likely to succumb to a MERS-CoV infection than a patient with SARS-CoV infection. Specifically, the CDC reports that from Nov 2002—July 2003 approximately 8,098 people were afflicted with SARS and 774 people died, a mortality rate of less than 10 percent.

While it is concerning that this virus has made its way all the way to the United States, it is even more important to be aware of the symptoms, treatment, and prevention of MERS. Common symptoms of MERS include fever, chills, cough, and shortness of breath. Muscle pain and gastrointestinal issues have also been noted. These symptoms can indicate a variety of much more common ailments than MERS, but the WHO is advising physicians to test patients who have returned from the Middle East within two weeks of falling ill.

The transmission of MERS is still under investigation. Researchers calculate that 75 percent of recent cases are “secondary cases,” meaning infected individuals have acquired the virus from another infected person. It is important to note that the majority of secondary cases are healthcare workers exposed to patients sick with MERS.

There isn’t a cure for MERS, but patients may be supported with breathing machines and antibiotics for potential secondary bacterial infections. However, just as the curative treatment for the virus causing the common cold is elusive, there is no cure for MERS and doctors do their best to allow the patient’s immune system to gain the upper hand over the virus. The absence of a cure makes prevention an imperative consideration. Organizations such as the CDC and the World Health Organization (WHO) encourage appropriate hygiene measures, such as regular hand washing, avoiding livestock, and maintaining proper food hygiene procedures.

Though it is curious that the first case of MERS emerged in the heart of the United States, it is important to note that the risk of significant transmission of MERS in America is actually quite low.

This travel-linked event brings to light a paradigm that public health officials have accepted: in an increasingly interconnected world, infectious diseases can make enormous geographic leaps with ease.