FREETOWN, Sierra Leone (AP) — A leading virologist who risked his own life to treat dozens of Ebola patients died yesterday from the disease, officials said, as a major regional airline announced it was suspending flights to the cities hardest hit by an outbreak that has killed more than 670 people.

Dr Sheik Humarr Khan, who was praised as a national hero for treating the disease in Sierra Leone, was confirmed dead by health ministry officials there. He had been hospitalised in quarantine.

Health workers have been especially vulnerable to contracting Ebola, which is spread through bodily fluids such as saliva, sweat, blood and urine. Two American health workers are currently hospitalised with Ebola in neighbouring Liberia.

The Ebola outbreak is the largest in history with deaths blamed on the disease not only in Sierra Leone and Liberia, but also Guinea and Nigeria. The disease has no vaccine and no specific treatment, with a fatality rate of at least 60 per cent.

Binyah Kesselly, chairman of the Liberia Airport Authority board, said police are now present at the airport in Monrovia to enforce screening of passengers.

“So if you have a flight and you are not complying with the rules, we will not allow you to board,” he said.

In a statement released yesterday, airline ASKY said it was temporarily halting flights not only to Monrovia but also to Freetown, Sierra Leone. Flights will continue to the capital of the third major country where people have died — Guinea — though passengers departing from there will be “screened for signs of the virus”.

Passengers at the airline’s hub in Lome, Togo, also will be screened by medical teams, it said.

“ASKY is determined to keep its passengers and staff safe during this unsettling time,” the statement said.

The measures follow the death Friday of a 40-year-old American man of Liberian descent, who had taken several flights on ASKY, causing widespread fear at a time when the outbreak shows no signs of slowing in West Africa.