The decade of the Coronavirus: What SARS and MERS have taught us about containing potential pandemics

MERS NIAID
Colorized transmission electron micrograph of the Middle East respiratory syndrome coronavirus (Credit: NIAID via Flickr used under CC license)

In 2002 the first cases of a strange new flu-like illness began appearing in southern China.  As case numbers mounted well into 2003, it became clear that this was not the flu. Patients began dying as their lungs filled with fluid and stopped functioning. Researchers rushed to determine what kind of virus was causing this disease before it could spread past hope of containment.

After the hard work of many dedicated individuals, it was determined that this new lethal virus was in fact a coronavirus (later named Sever Acute Respratory Syndrom virus, or SARS-CoV). This was odd, as this kind of virus was not known to cause serious disease in humans before this point. By comparing this new virus to older samples, it was determined that this virus was originally living in bats before jumping to civets, and then finally humans. Thankfully, due to this varied zoonotic background (which means to come from animals), SARS did not have the best person-to-person transmissibility during the early parts of the outbreak and was eventually contained once health care officials new what to look for and quarantine. Once the numbers were tallied it was determined that SARS infected over 8000 people, killing over 700 of the most unfortunate individuals. This would not be the last time a coronaviruses would make a dramatic jump into human hosts. In 2012 we were tested on what we learned during the first SARS outbreak in 2002.Fast forward ten years and we are experiencing a similar, yet smaller, outbreak; but this time in the Middle East as opposed to East Asia. This new  virus is also a coronavirus, now named Middle Eastern respiratory syndrome coronavirus (MERS-CoV), but as of yet scientists have been unable to find the host species of this new strain. Bats and camels are under suspicion of being reservoirs but have not been confirmed. Because of this lack of understanding of the MERS viral ecology it is very difficult to develop plans to contain outbreaks, but we have learned valuable lessons from SARS a decade ago.

As of writing, the most recent WHO-confirmed case of MERS-CoV was on October 18th in Qatar in a 61 year old man. This confirmed case marks the 139th laboratory confirmed case since September of 2012 when the virus first emerged (60 of which have been fatal).  This man did work at a farm that had many species of animals present, including camels. However, when researchers analyzed samples from the different animals present on site they were unable to isolate any MERS-CoV from the samples. As a result, there is no clear picture of how this man, or any of the other patients, acquired this virus from the environment. How people get this virus remains a mystery.

We know that there are viruses in the environment that we’ve never encountered and in some cases never even imagined (see the recent Pandoravirus discovery for a recent, if rather harmless, example of paradigm-expanding microbes). Scientists and medical staff in the Middle East are now paying close attention to any patients coming in that may be exhibiting symptoms of sever acute respiratory infections (SARI) (see image below) and quarantine suspected cases until a diagnosis can be completed.

A chest x-ray showing increased opacity in bot...
A chest x-ray showing increased opacity in both lungs, indicative of pneumonia, in a patient with SARS. (Photo credit: Wikipedia)

One of the SARS outbreaks that occurred in 2003 was due to an infected patient being admitted to a hospital in Canada, where medical professionals were not actively looking for patients with this disease. As a result, the SARS patient was not properly quarantined and the virus managed to spread in the hospital to other patients, resulting in approximately 400 cases, 44 fatalities, and over 25,000 Canadians were quarantined to prevent further spread of the disease. Thanks to this knowledge, we were much more prepared to quarantine suspected cases when MERS first appeared in 2012. Patients that presented with symptoms of SARI would be screened to rule out recent travel to the Middle East or contact with someone from the region. In this way hospital systems were able to catch imported cases of the disease before they could spread

Thankfully, due to modern disease surveillance and new, faster technologies that allow for rapid diagnosis we have been able to contain both SARS and MERS (so far). But just because they were contained at the moment doesn’t mean that we are safe from the continued emergence of new zoonotic viruses.

This fact is not something that we can lose sight of: the natural world is a reservoir for many diseases, some of which may be fatal to humans, and there is no way to know when or where the cross-species jump will occur. In this sense SARS and MERS have been good tests of just how well we can contain new emerging disease and have given us much information on how we can further improve the safety of humanity. It is up to us to learn from these lessons and properly implement what we learn in order to prevent future pandemic events.

To stay up-to-date on MERS activity in the Middle East and elsewhere I recommend taking a moment to look at WHO Disease Outbreak News.

Featured Image from flickr user NIAID used under creative commons license.

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