May 3, 2014
Camels, SARS, And First US Case: MERS Coronavirus Picks Up Steam
Lawrence LeBlond for redOrbit.com - Your Universe Online
With the ongoing threat of the dangerous Middle East Respiratory Syndrome (MERS) coronavirus, experts have been feverishly looking for a source of the infection, which has so far claimed the lives of more than 130 people since first being detected in June 2012 – and first reported three months later in September 2012.
Studies on the virus have revolved around bats, goats, sheep, and camels, with the most reliable sources having been camels, based on several recent reports. A study conducted by scientists at the University of Veterinary Medicine in Vienna shows that the MERS coronavirus in man and camels from a single region are most identical. Their findings, which indicate the virus has been transmitted from camels to humans, is published in the journal Eurosurveillance.
While it has been confirmed recently that the Arabian camel is the origin of the infectious disease, the transmission pathways of the disease have not been clear until now.
Norbert Nowotny and Jolanta Kolodziejek, virologists from the Institute of Virology, have been investigating the transmission pathways of the MERS coronavirus and found that the virus from infected humans and Arabian camels from the same geographical region share nearly identical RNA sequences.
"This indicates transmission between animals and man. The process is referred to as zoonosis. With this knowledge we can specifically react to the spread of the virus. Vaccinations of camels are currently being discussed. We will thus be able to halt the spread of the virus," Nowotny said in a statement.
In studying camels from the Oman region, researchers found five with MERS coronavirus and compared the RNA sequence with those of MERS coronavirus from Qatar and Egypt. Their analyses showed that the viruses differ from region to region.
"This means that there is no specific 'camel MERS coronavirus strain', but that one virus infects both, camels and humans," said Nowotny.
The researchers found that virus levels were surprisingly high in the nasal mucosa and conjunctiva of camels. Therefore they presume that the transmission pathway from animals to humans most likely occurs through these contact sites, especially through nasal discharge.
While MERS causes severe pneumonia and renal failure in humans, camels show little to no symptoms, except for occasional nasal discharge.
MERS is similar to the SARS coronavirus that originated in China and killed nearly 800 people around the world in 2002 and 2003.
"While the SARS coronavirus probably crossed the species barrier only once by passing from bats to humans, we may presume that the MERS coronavirus is being constantly transmitted from camels to humans," explained Nowotny.
Nowotny and colleagues in a previous study (www.sciencedirect.com/science/article/pii/S1473309913701646) showed that MERS coronaviruses do in fact infect camels, after discovering antibodies against the virus in the dromedary animals. The current genetic analysis of MERS permits more exact conclusions.
LESSONS FROM SARS
While MERS and SARS share similarities, there is a distinction to be drawn. SARS sickened more than 8,000 people in 2002 and 2003, of which nearly 10 percent died. With MERS, so far only 424 cases have been detected since the first reported case in September 2012. However, the fatality rate is much higher in MERS, killing about a third of patients infected.
Another distinction between the two coronaviruses is prevalence. SARS was a global killer, while MERS has mostly been confined to the Middle East. There have been some cases reported outside the Middle East, but all were in people who either had traveled to the Middle East or was in close contact with the infected traveler.
Despite MERS’ higher incidence of death, it is still not yet a global concern, according to Marc Sprenger, director of the European Centre for Disease Control (ECDC).
"Even though our understanding of MERS is only a slowly evolving one, we can see important differences between it and SARS," Sprenger told CNN via email. "Perhaps the most important one is that MERS is spreading much slower than SARS -- we have not yet seen sustained human to human transmission.”
"A similarity with SARS is that both SARS and MERS are zoonotic (when the virus can jump from animal to human) viruses. MERS appears to be a zoonotic virus resulting from multiple introductions and re-introductions into the (human) community," he explained.
While MERS has been slow to infect large numbers of people over a short period of time, there has been a recent uptick in cases. An alarming spike has been recorded over the past week, both in case numbers and deaths. According to Arab News, 16 cases of MERS have been reported in the last 24 hours. As well, ECDC figures show that more cases have been reported in April of 2014 than all of the past 18 months combined.
The protocols Hong Kong and other countries honed in on following the SARS outbreak in 2002 and 2003 offer the best measures at limiting the spread of coronaviruses. Knowledge, in the form of public education, is key to halting the spread of coronaviruses.
Saudi Arabia is now learning transparency, which is key to combating the deadly disease. Evidence of this is seen in the recent replacement of the country’s secretive health minister Abdullah Al-Rabeeah. The country swore in Adel Fakieh, who is a proponent of public education and openness.
The emergence of SARS not only took the world by surprise, noted Prof. Malik Peiris, director of Hong Kong University’s School of Public Health, but it also marked the re-emergence of infectious diseases as a major global concern.
In the wake of SARS, Hong Kong has now become a center for infectious disease epidemiology and virology, Peiris said. As well, public education about hygiene and disease containment in Asia and around the world are much better following SARS.
"The consciousness of hygiene, issues of coughing and sneezing in public, the use of hand wipes and alcohol wipes ... and people wearing masks when they have respiration infection -- importantly, that is not to protect themselves but to protect others (from infection)," Peiris told CNN's Euan McKirdy. "These are direct results of SARS."
The research into antibodies developed at the time of SARS has been invaluable in the development of MERS studies, and the models of virus behavior developed during the 2003 SARS outbreak have added to the urgency of developing an antidote for MERS before it becomes a global pandemic, according to a South China Morning Post report.
"The MERS coronavirus may undergo further genetic changes and one day become as transmissible as the SARS coronavirus," Professor Yuen Kwok-yung, an expert in infectious diseases at the University of Hong Kong, told the newspaper. "Therefore we must prepare for this scenario before it happens."
DANGER IN AMERICA
While there have only been limited numbers of cases reported outside the Middle East, US health experts have been monitoring the disease closely in case of signs of the virus on American soil.
To date, MERS cases outside the Middle East have been confined to the Old World. Today, however, the first human case of infection from MERS has been diagnosed inside the United States.
The case is in a health worker who had traveled to Saudi Arabia. The male patient had traveled via British Airways on April 24 from Riyadh to London and then taking a connecting flight from Heathrow to the US. He landed in Chicago and took a bus to an undisclosed city in Indiana.
The man began experiencing respiratory ailments on April 27 – including cough, shortness of breath, as well as fever – and checked into the ER at Community Hospital in Munster, Indiana on April 28, being admitted the same day.
Because of his travel history, Indiana health officials took a blood sample and sent it off to the US Centers for Disease Control and Prevention (CDC) for MERS testing. The health agency returned a confirmation on the sample on Friday, May 2.
Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, said on a conference call the first US case of MERS was "of great concern because of its virulence," proving fatal in about a third of infections, reported Reuters.
Still, Schuchat maintains the case represents “a very low risk to the broader general public,” but MERS has been shown to spread to healthcare workers and there are no known treatments for the disease.
At the time of this report, the patient is in stable condition with no other suspected cases of MERS on US soil.
“It was only a matter of time before the United States had a case,” virologist Dr. W. Ian Lipkin, of Columbia University in New York, told Reuters reporters Julie Steenhuysen and Sharon Begley. “Most of us thought it was not a question of if, but when. Am I more concerned as a result of this case? No.”
He maintained that the greatest reason why he is not overly concerned is because, despite the limited knowledge of the virus and its transmission pathways, the virus has been largely associated with bats and camels, with camels being the most likely reservoir from which humans become infected.
And likely because MERS was a disease of the Old World with limited cases seen outside the Middle East, the US politicians and health experts had no reason to be overly concerned. But with a case now confirmed in the US, things may begin to change.
“Now the U.S. is going to be more interested. I think it will have an impact on the number of scientists here who will be encouraged to work on MERS and congressmen will stand up and rail about the importance of this,” Lipkin added.