LONDON (AFP) - A Qatari man has died in a British hospital from the Middle East Respiratory Syndrome (MERS) virus which has been causing increasing alarm among world health experts, officials said Thursday.

The death brings to 43 the number of people to date who have died from the SARS-like infection, which has an extremely high mortality rate.

The unnamed 49-year-old man had been in a London hospital since September 2012 receiving treatment for acute symptoms from the virus, having earlier been airlifted from the Qatari capital Doha.

The man had previously travelled to Saudi Arabia where the majority of cases have been concentrated.

He died last week after his condition sharply deteriorated, a spokeswoman for Guy's and St Thomas' hospital said.

"Guy's and St Thomas' can confirm that the patient with severe respiratory illness due to novel coronavirus (MERS-nCV) sadly died on Friday 28 June, after his condition deteriorated despite every effort and full supportive treatment," the spokeswoman said.

MERS is a member of the coronavirus family, which includes the pathogen that causes Severe Acute Respiratory Syndrome (SARS).

The World Health Organization (WHO) said on June 26 that 77 laboratory-confirmed cases had surfaced worldwide with 40 deaths. Saudi Arabia announced two further deaths on Wednesday.

SARS sparked global panic in 2003 after it jumped to humans from animals in Asia and killed some 800 people.

Like SARS, MERS appears to cause a lung infection, with patients suffering from fever, coughing and breathing difficulties. But it differs in that it also causes rapid kidney failure.

While most of the cases have been concentrated in Saudi Arabia, the MERS virus has also spread to neighbouring Jordan, Qatar and the United Arab Emirates.

Cases have also been found in France, Germany, Italy, Tunisia and Britain, although most of these patients had been transferred for care from the Middle East or had travelled to the Middle East and became ill after they returned, the WHO said.