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Deadly MERS 'camel flu' may now be airborne

10:45am Thursday 24th July 2014 content supplied by

More specifically, the WHO advises that people avoid close contact with animals - particularly camels - when visiting farms, markets or barn areas where the virus is known to be circulating. People should also avoid drinking raw camel milk or camel urine, or eating meat that has not been properly cooked.

Where did the story come from?

The study was carried out by researchers from King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia, and was funded by the same institution.

The study was published in the American Society for Microbiology, a peer-reviewed science journal.

This whole journal is open-access, meaning that anyone can read the publications for free online, including this latest research.

The study highlights new research into the origins and possible transmission of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) - a new human virus that causes severe respiratory symptoms and kidney failure.

Since it was recognised, the WHO reports there have been 837 laboratory confirmed cases in humans, and at least 291 deaths.

The authors report that these have been in at least 17 countries in Asia, Africa, Europe and North America - most originated from countries in the Arabian Peninsula, including Saudi Arabia.

They say the virus has the ability to infect close contacts such as family members and healthcare workers, and that it causes the death of many of those affected. This means the virus is a potential global public health threat. A case death rate of just under 30% is unusually high for a respiratory virus, a statistic that has sparked concern.

The authors say the origin and transmission of MERS is not fully understood, but it seems humans could contract it through direct contact with infected camels. However, intermediate steps in this process have been suggested, as well as airborne transmission.

This latest research aimed to investigate whether MERS-CoV might be transmitted from camels to humans via the air.

What kind of research was this?

This was a laboratory analysis of air samples collected from a camel barn in Saudi Arabia.

The researchers knew of a man and some of his nine camels that had contracted exactly the same MERS virus (100% identical when tested in the lab), suggesting that the camels had infected the man. 

However, it was not clear whether the man contracted the virus from touching the camels or from breathing in air containing the virus originating from the camels.

What did the research involve?

The researchers tested the air from the barn where the infected camels were housed for traces of the MERS virus to see if, at least in theory, it was possible for the virus to be transmitted through the air.

The man became unwell on October 26 2013 and reported that four of his camels had suffered respiratory illness since October 19. He was admitted to an intensive care unit (ICU) on November 3 2013. Three air samples were collected from the camel barn on three consecutive days from November 7. All three samples were screened for the presence of the MERS virus genetic material, and the camels were tested for the MERS-CoV infection.

The man died on November 18 2013; his camels appear to have survived.

What were the basic results?

Only the first air sample tested positive for airborne MERS genetic material. The other two samples, collected in the next two days, were negative. The authors note that the first sample was collected on the same day as one of the nine camels also tested positive for the MERS infection, although four of the nine camels had been showing signs of respiratory illness for many weeks.

They confirmed that the genetic fragments from the air were 100% identical to fragments found in the infected man and the infected camel. This, they said, suggested that the genetic material in the air had originated from the infected camel.

The virus material from the air samples was not able to infect cells in the laboratory, indicating there may have been loss of viral infectivity from the air sample.

How did the researchers interpret the results?

The authors say the data suggests that, "camels may be a source of infectious MERS-CoV, which can be transmitted to humans within confined spaces" and that, "these results also suggest that air sampling might be a useful approach to investigate the role of the airborne transmission of MERS-CoV spread and shedding."

They added that, "further studies are urgently needed to fully understand the role of camels in the transmission of MERS-CoV and whether airborne transmission plays a role in MERS-CoV spread, in order to implement control and prevention measures to prevent the transmission of this deadly virus."

Conclusion

This genetic research found genetic fragments from the MERS virus in an air sample of a barn housing MERS-infected camels. This raises the possibility that the owner contracted the MERS virus from airborne transmission, rather than through direct contact, as had previously been assumed.

However, it is important to realise that, based on this research alone, there is no concrete evidence to suggest the transmission was airborne, only that it is a possibility to investigate further.

It was also unusual that the virus was only detected in one of the three air samples, taken 12 days after the onset of illness and four days after the man had been admitted to an ICU. There could be many explanations for this - such as ventilation in the barn. 

Either way, it highlights that more investigation is needed to establish whether the MERS virus, or at least some strains of it, is regularly airborne and how long it may stay airborne.

Research needs to establish how MERS infection is spread between camels and humans, and whether this can happen through the air. If it can, this makes the virus more likely to spread quicker and more widely, like other airborne diseases, such as flu. Research also needs to establish whether the MERS virus can remain infectious when on surfaces, which may be touched by people, providing further indirect infection routes.

This study is important because the MERS virus is new, so is not yet fully understood. It will be important to keep researching this virus and tracking its spread to better understand how it is transmitted to humans. This will, ultimately, help inform better prevention or control measures, thereby protecting people from this potentially fatal infection.

In the meantime, the WHO recommends strict control measures such as gloves, mask and eye protection for healthcare workers when caring for affected individuals. There are as yet no travel or trade restrictions, and no screening recommendations for entry into other countries.

Read the latest WHO Disease outbreak news here.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Summary

"Deadly Mers virus 'could now be airborne'," The Independent reports. Air samples suggest that the Middle East Respiratory Syndrome virus, which has an estimated 30% case fatality rate, could now be spread through the air...

Links to Headlines

Deadly Mers virus 'could now be airborne', warn scientists in study on Saudi Arabian barn. The Independent, July 22 2014

Deadly MERS virus 'may be airborne', sparking fears it may spread quicker. Mail Online, July 23 2014

Links to Science

Azhar EI, Hashem AM, El-Kafraw SA, et al. Detection of the Middle East Respiratory Syndrome Coronavirus Genome in an Air Sample Originating from a Camel Barn Owned by an Infected Patient. mBio. Published online July 22 2014

Useful Links

• NHS Choices links
• Camels may be source of MERS virus transmission
• Novel coronavirus 'limited' spread between people
• Healthcare abroad