Fragments of the Middle East
Respiratory Syndrome coronavirus (MERS-CoV) have been found in the
air, suggesting it has the potential to be transmitted this
The air samples were taken from a barn housing camels afflicted
with the disease, a team of virologists from Saudi Arabia –
where the virus first surfaced in 2012 — explain in a paper
published in mBio.
Camels are thought to be the animal reservoir of the virus, but
little is know about how it is transmitted to humans. We are closer
to confirming the animal’s role, however, after an investigation in
Qatar suggested those working closely with camels are at higher
risk of infection and another study revealed MERS-CoV antibodies
had been identified in the animal. Both results suggest, says the
World Health Organisation, that camels are indeed the “likely primary source“ of human infection,
not bats as was first presumed.
Around 700 cases of the virus have been reported since 2012, and
208 of those people have since died. It has been assumed that close
contact with infected individuals and, potentially, persistent
contact with infected animals has been the main cause of the virus
spread. The exact parameters of that transmission, however, are
still not known. And this latest study presents a troubling
suggestion that it could in fact be an airborne delivery.
The Saudi Arabian team had been investigating a potential case
of MERS-CoV being transmitted to the owner of four infected camels.
During that study, they collected three air samples in November
2013 over a period of days from the barn in which the animals
resided. The owner’s camels had exhibited signs of the disease just
one week before he fell ill — he had even administered a nasal
treatment to one of these camels.
The air samples were immediately analysed using a reverse
transcription polymerase chain reaction test that is used to
identify RNA. Only one sample came back as being positive for signs
of the virus — the sample that was collected on the first day. On
that same day, at the start of the intervention, one of the camels
was diagnosed as having MERS-CoV. To confirm the find, the
researchers also did a partial genome sequence on the fragment.
Finally, these results were compared with those from the now
deceased owner. It showed that “the virus is identical to the
original isolates obtained from the nasal samples collected from
the patient and the infected camel” — the owner and the camel both
had the same strain, and that same strain was in the air.
The fact that the virus was not identified in the other two
samples, collected after the camels had been removed, does however
suggest it does not linger long in the air.
There is no MERS-CoV vaccine — and no specific treatment — in
existence. Physicians will treat the symptoms, but survival is
often down to the individual’s age and immune system. The World
Health Organisation has been working with animal health agencies to
spread the word on general good practice for people working in
close contact with animals. However, this latest revelation
suggests far more stringent procedures could be key to stalling the
So far MERS-CoV — thought to be deadlier than SARS, but harder
to transmit — has largely been contained to countries in close
proximity to Saudi Arabia, including Iran, Jordan, and the UAE. The
fact that more than two million people flock to Saudi Arabia every
year on a religious pilgrimage does somewhat increase the chances
of the illness spreading further afield — but this has so far not
been too much of an issue, bar two cases in the Netherlands, one in Algeria and several in the US.
The study’s authors are however calling for caution, while
further investigations are pending.
“The clear message here is that detection of airborne MERS-CoV
molecules, which were 100 percent identical with the viral genomic
sequence detected from a camel actively shedding the virus in the
same barn on the same day, warrants further investigations and
measures to prevent possible airborne transmission of this deadly
virus,” said lead author Esam Azhar, head of the Special Infectious
Agents Unit at King Fahd Medical Research Centre and associate
professor of medical virology at King Abdulaziz University in
Jeddah. “This study also underscores the importance of obtaining a
detailed clinical history with particular emphasis on any animal
exposure for any MERS-CoV case, especially because recent reports
suggest higher risk of MERS-CoV infections among people working
A meeting held by the World Health Organisation in May decided, despite a spike in
reported cases of the virus in April, it was not time to declare a
public health emergency. The group ruled that there was “no
evidence of sustained human-to-human transmission in communities”,
but that affected countries had to up their basic infection
prevention measures and improve awareness.