First identified in 2012, the Middle East Respiratory Syndrome virus has caused acute respiratory illness in around 900 people from the Arabian Peninsula. Previous research has suggested that camels could be a carrier of the virus, passing it to humans, but a new study has confirmed for the first time that camels actually emit volumes of the virus – making them suspect number one for spreading it to humans.
Image credit: CSU
The research team comes from Colorado State University (CSU), where, in the Animal Reproduction and Biotechnology Laboratory, they were able to care for their camels in a sealed Biosafety Level 3 Laboratory.
This is one of the only research institutions in the US that is equipped to safely conduct tests on camels with such a contagious virus, and the CSU team worked with an arm of the National Institutes of Health (NIH).
The Middle East Respiratory Syndrome (MERS) virus is a coronavirus causing – in most cases – fever, cough and shortness of breath. In total, around 30% of people with confirmed MERS virus infection have died.
Though all of the cases have been linked to countries around the Arabian Peninsula, in May of this year, there were two confirmed imported MERS cases in the US from two people traveling from Saudi Arabia; the cases were not linked.
Danielle Adney, a PhD student from CSU’s Department of Microbiology, Immunology and Pathology, lead the study, which will be published in the journal Emerging Infectious Diseases.
From the study, Adney and colleagues showed that three infected dromedary camels emitted high levels of the MERS virus – primarily from the nostrils. Additionally, the researchers found that the virus develops in the animals’ upper respiratory system and they shed the infectious virus for up to a week.
Within weeks, the camels overcame the virus as if it were a common cold, the team adds.
Commenting on their findings, principal investigator Prof. Richard Bowen, from CSU’s Department of Biomedical Sciences, says:
“It would be very surprising, given the amount they are shedding, if they were not able to infect other camels and humans. It strongly supports the theory of camels being the primary reservoir for this virus. Until this study, people knew infected camels shed some virus and carried it, but it was mostly circumstantial evidence.”
Confirming camels as a source is crucial to advancing knowledge and solutions for this infectious virus. Mark Pallansch, director of the Division of Viral Diseases at the Centers for Disease Control and Prevention (CDC) calls the finding a “necessary step,” adding:
“We don’t have an effective intervention for stopping the spread of the virus other than standard hygiene precautions and avoiding contact with infected individuals. This does provide a possible intervention to keep the host from infecting humans.”
The researchers are now testing a vaccine that could keep camels from shedding the MERS virus. In early August, they gave the animals the experimental vaccine with the hope that it would eliminate or at least reduce the amount of virus the camels shed.
- Health officials first reported the disease in Saudi Arabia in 2012, but they later found the first case occurred in Jordan in April 2012
- Current information suggests the incubation period for MERS is 2-14 days
- Around 30% of people with confirmed MERS infection have died.
The vaccine, developed by the NIH, contains a harmless protein found in MERS that should trigger antibodies to fight the virus.
Though other research groups are working on MERS vaccines, the CSU-NIH team is the only one testing theirs on camels.
Prof. Bowen says the “concept is to vaccinate the camels to protect the people.” He adds that, if effective, they would have the “tools to vaccinate camels and prevent transmission from occurring.”
Co-principal investigator Vincent Munster, chief of virus ecology in the NIH National Institute of Allergy and Infectious Disease, says “this would be a pretty big step, that you could use a vaccine in camels to control human disease.”
“The bigger step would be to get countries like Saudi Arabia and Qatar to begin administering the vaccine to tens of thousands of camels,” he adds.
In September 2013, researchers who used advanced DNA analysis techniques to analyze MERS genomes taken directly from MERS patients were able to “reconstruct” where, when and how the virus has evolved. Their results suggested the virus centered around the Riyadh area of Saudi Arabia.