Saudi scientists have found gene fragments of the deadly Middle East Respiratory Syndrome virus in air samples from a barn housing an infected camel and say this suggests the disease can be transmitted through the air.

MERS, a serious respiratory illness caused by a coronavirus, has infected at least 850 people since it first emerged two years ago and killed at least 327 of them, according to latest figures from the European Center for Disease Prevention and Control.

The vast majority of human cases have been in Saudi Arabia, but isolated MERS cases have been reported across Europe and in Asia, as well as in the United States in people who have recently traveled in the Middle East.

Scientists are not sure of the origin of the virus, but several studies have linked it to camels, and some experts think it is being passed to humans through close physical contact or through the consumption of camel meat or milk.

However, in this latest study, published in the online journal of the American Society for Microbiology, mBio, scientists said the detection of the virus in air samples was concerning and needed to be followed up.

"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 Esam Azhar, an associate professor of medical virology at King Abdulaziz University in Jeddah who led the study.

Viruses that spread through air - flu, for example - are far more likely to spread swiftly and widely in human populations than those that can only move from an animal to a person, or from person to person, via direct contact.

For their research, Azhar's team collected three air samples on three consecutive days from a camel barn near Jeddah owned by a 43-year-old male MERS patient who later died from the disease.

Four of the man's nine camels had shown signs of nasal discharge the week before the patient became ill, and he had applied a topical medicine in the nose of one of the sick camels a week before he experienced symptoms.

Using a laboratory technique called reverse transcription polymerase chain reaction to detect levels of particular genes, the scientists found that the first air sample, collected on Nov 7, contained genetic fragments of the MERS virus.

This was the same day that one of the patient's camels tested positive for the disease, they said in a report.

The other samples did not test positive for MERS, Azhar said. Further tests of the first air sample confirmed the presence of MERS genetic sequences and showed that the fragments were identical to those detected in the camel and its sick owner.