Related to the common cold, the new coronavirus first detected in the Middle East could be spreading from human to human.

A third suspected case of the potentially fatal coronavirus (nCoV) has been detected in France. It follows the hospitalisation of a 65-year-old who is the first confirmed case of the respiratory illness in France. He remains in a stable but critical condition.

A nurse in a hospital in Douai where the patient was first referred has been placed under watch since Thursday night. A doctor and another patient remain in isolation as tests are carried out. If they return positive results, it could mean that person to person transmission is occurring.

France is the third European country to be hit by the virus which appears to originate in the Middle East. The Frenchman (whose name has not been released) had returned from Dubai late April and was admitted to hospital on his return with digestive problems.

In the UK three members of the same family were infected after a relative returned from Pakistan and the Middle East. As with the bird flu, family members may be more susceptible to contagion than other members of the public. Germany has also been hit with two cases. Both had travelled in the Arabian peninsula, one died and one recovered.

A single hospital, Al-Moosa in the town of Hofuf, Saudi Arabia has reported 23 cases, suggesting it could be spreading through hospitals. The World Health Organisation (WHO) has travelled to Saudi Arabia to investigate how the virus is being transmitted. They are worried about the clusters of cases being a potential for a pandemic. The Saudi Health Ministry suggested that the cluster observed in the single hospital suggested nosocomial transmission. Patients may have had increased susceptibility to infection or severe disease because of their multiple illnesses. However, two family members of patients have contracted the virus suggesting it is being transmitted amongst the community.

The virus attacks the respiratory system causing pneumonia and potentially kidney failure. The WHO has advised all countries to test patients with unexplained pneumonia. World Health Organisation alert web page latest update

There have been 33 cases reported since September 2012, with 18 of them dying. The 50 per cent death rate indicates the coronavirus is more aggressive than SARS (severe acute respiratory syndrome) which killed some 800 people in 2003, which had a death rate of 11 per cent. The WHO have released guidelines for prevention and control of the virus

The source of the virus is unknown, though the most popular theory is that it is related to a virus strain found in bats. The SARS virus which originated in China proved that intermediate animal hosts may sometimes play an important role in transmission to humans and that direct exposure to animals is not needed for infection. Identifying the source will require the cooperation of veterinary services, food safety authorities, environmental health agencies as well as public health authorities.