A 38-year-old man is being treated in isolation after being confirmed as having the potentially deadly Crimean-Congo haemorrhagic fever.

The patient, who returned to Glasgow on a connecting flight from Dubai on Tuesday, is in a critical condition at Gartnavel General Hospital's Brownlee Centre, which specialises in infectious diseases.

He was admitted to hospital within three hours of his arrival in the city and NHS Greater Glasgow and Clyde said all the appropriate infection control measures are in place.

Laboratory test results confirmed today that he has Crimean- Congo haemorrhagic fever (CCHF), a widespread tick-borne viral disease which is especially common in East and West Africa and can affect humans.

The health board said the risk of person-to-person transmission of the virus is "extremely low" as it is not passed through the air.

However, as a precautionary measure, it said those who have been in close contact with the man are being traced directly to ensure that there has been no transmission, including three passengers who were seated in close proximity to him on Emirates flight EK027 flight from Dubai.

In a statement tonight, NHS Greater Glasgow and Clyde said: "The risk to all other passengers on the flight is extremely low; however, if they have any concerns they should contact NHS24 on 08000 858531 for advice, further information and reassurance.

"Given the fact that this man went into the care of the NHS within three hours of his flight arrival in Glasgow and travelled directly home via private transport from the airport, we are confident that his close contacts subsequently within the city were minimal.

"We have also identified all NHS staff, airport and airline staff who have had contact with the patient and any necessary follow-up action will be taken."

The onset of CCHF is sudden and is often severe in infected humans, with a mortality rate of up to 30%.

Outbreaks of the illness are usually attributable to contact with blood or body fluids from infected animals or people, the health board said.

Initial signs include headache, high fever, back pain, joint pain, stomach pain, and vomiting.

Red eyes, a flushed face, a red throat, and red spots on the roof of the mouth are also common.

Symptoms may also include jaundice, and in severe cases, changes in mood and sensory perception.

As the illness progresses, large areas of severe bruising, nosebleeds and uncontrolled bleeding at injection sites can be seen, beginning on about the fourth day of illness and lasting for about two weeks.

Dr Syed Ahmed, NHS Greater Glasgow and Clyde consultant in public health, is co-ordinating an investigation into the case, along with colleagues from Health Protection Scotland and the Health Protection Agency.

"The risk of person-to-person transmission of Crimean-Congo viral haemorrhagic fever is extremely low as it can only be transmitted by direct contact with infected blood or body fluids," he said.

"It is not a virus which is transmitted through the air. As such the risk to those who were in close contact with him is minimal.

"Crimean-Congo viral haemorrhagic fever is a widespread tick-borne viral disease.

"It is not common in Western Europe but is endemic in parts of Eastern and Southern Europe, central Asia, Africa, the Middle East and the Indian subcontinent.

"It is caused by infection with a tick-borne virus (Nairovirus) in the family Bunyaviridae.

"As soon as laboratory sampling confirmed that the patient was suffering from this virus, all the appropriate agencies were informed."