By Barry C. Fox, M.D., University of Wisconsin
With the emergence of new viruses, and the experience with Ebola in the United States, stringent protocols have been put in place by the CDC to rapidly diagnose patients and contain the illness. In addition, the CDC continues to upgrade preparedness for airline and airport staff who are crucial to the containment efforts.
A startling announcement came in 2014 that the first case of Middle East Respiratory Virus Syndrome or MERS had invaded the United States. MERS first surfaced in the Middle East in 2012 and most cases had previously only occurred on the Arabian Peninsula.
In 2014, MERS was brought to the United States by a healthcare worker who had been in Saudi Arabia caring for hospital patients. He left Saudi Arabia traveling by plane to London, and then on to Chicago, where he took a bus to Indiana, and began to feel ill with shortness of breath, coughing and fever. Based on his symptoms, the travel history, and his blood test, the CDC confirmed MERS.
It had been ten years since the original Severe Acute Respiratory Syndrome, or SARS outbreak of 2003 had happened.
This is a transcript from the video series An Introduction to Infectious Diseases. Watch it now, on Wondrium.
Both the SARS and MERS viruses are part of the Coronavirus family. Coronaviruses are known for the crown-like spikes on their surfaces. The virus causes disease in the lungs with a bloody pneumonia. Importantly, Coronaviruses can remain suspended in the air and travel more than 8 feet. They can be transmitted from person to person.
The World Health Organization, or WHO, is concerned about MERS. Nobody knows what the reservoir is, or how it is transmitted.
Spread of the MERS Virus
An unlikely animal reservoir was discovered in Saudi Arabia, a camel. However, it was unclear if the camel was actually the direct source of the virus, or just a vector of transmission to humans.
In one instance, a Malaysian man died of MERS contracted from drinking camel’s milk. After studying the milk, it was found that the MERS virus can live in camel’s milk for up to 72 hours. The other postulated reservoir is, once again, bats.
The WHO is particularly worried about opportunities for spread of the MERS virus amongst large communities and large gatherings.
While the containment of the disease is possible with the old-fashioned quarantine, there is, however, no vaccine or any specific treatment for MERS or SARS. The WHO can only implement reporting requirements and early identification measures for MERS.
Learn more about the life cycle of a virus.
The West Nile Virus
Another virus emerging in the United States is the West Nile virus. This virus was first detected in the United States in 1999, although it was found in Israel in the 1950s and spread throughout Europe, North Africa and Asia over the next decades.
Interestingly, one of America’s favorite and most identifiable birds, the American Robin, was found to be one of the most prevalent carriers of West Nile virus. In Chicago, the robin is known as the super-spreader of the West Nile virus.
However, it is the mosquitos that actually serve as the vector of the disease. They bite the robin, which harbors the virus without symptoms, then the mosquitoes pass it on to humans.
In fact, a single storm sewer drain in Chicago was found by epidemiologists to be a huge breeding ground for mosquitos, and in 2005, Illinois had 400 cases of West Nile and 21 deaths.
Symptoms of the Disease
After being bitten by a virus infected mosquito, surprisingly more than half of all infected people are completely asymptomatic. Those who are symptomatic usually have a high fever and muscle aches for 48 hours, similar to, but not as severe as dengue, with resolution of the illness over the next few days.
However, those over the age of 50 are more prone to neurological symptoms that may include meningitis or even encephalitis, which could result in death. Fortunately, this is a rare occurrence.
Chikungunya is another emerging mosquito disease. It is a viral disease transmitted to humans by the bites of infected mosquitoes which are found across the globe. First described during an outbreak in southern Tanzania in 1952, the virus then spread to Africa, Asia, and the Indian subcontinent.
Originally believed to be a tropical disease, experts were surprised when an outbreak occurred in north-eastern Italy in 2007.
Now it has spread further, to 14 Caribbean island countries since it was first detected on the island of St. Martin in December 2013. In May 2014, the Caribbean Public Health Authority declared it an epidemic, with over 5000 probable cases across the region.
Chikungunya’s symptoms are very similar to dengue viral infection, although it may not be as severe, and deaths are exceedingly unusual.
Learn more about exotic diseases.
Appearance in the U.S.
Because the Caribbean islands are close to the United States, Chikungunya made its premiere appearance in the U.S. in 2014. The CDC has been working with its partners at airports with flights to the Caribbean to educate outgoing travelers about how to stay safe from chikungunya, and returning travelers about what symptoms to be on the lookout for.
All eyes are set on these globe-trotting viruses spreading deadly diseases and no one is taking them lightly. Needless to say, for now, monitoring will continue to ensure everything is in place to prevent an epidemic, and scientists will continue to study the viruses and their transmission.
Common Questions about Emerging Viruses and Diseases
Both SARS and MERS viruses are part of the Coronavirus family. Coronaviruses are known for the crown-like spikes on their surfaces. These viruses can remain suspended in the air and travel more than 8 feet, and can be transmitted from person to person.
The West Nile virus was first detected in the United States in 1999, although it was found in Israel in the 1950s and spread throughout Europe, North Africa and Asia over the next decades.
The Chikungunya virus initially spread to Africa, Asia, and the Indian subcontinent. Originally believed to be a tropical disease, experts were surprised when an outbreak occurred in north-eastern Italy in 2007.