Two of his fellow workers at the hospital who had tested positive at the same time have since died from the virus.
The epidemic, described as the worst since Ebola was discovered four decades ago, has now killed at least 1013 people in Guinea, Liberia, Sierra Leone and Nigeria according to the World Health Organisation, which said it is ethical to use unproven Ebola drugs and vaccines.
"There was unanimous agreement among the experts that in the special circumstances of this Ebola outbreak it is ethical to offer unregistered interventions as potential treatments or prevention," said Marie-Paule Kieny, the World Health Organisation's assistant director-general, after an ethics panel had published its guidance. A senior US health official assessing the crisis has warned that the scale of the outbreak in Liberia is overwhelming the capacity of the specialist isolation units that treat victims.
Dr Kevin De Cock, director for global health at America's Centre for Disease Control and Prevention, said one of the country's two main treatment clinics, in Lofa County, had 80 patients in a 20-bed unit.
Separately, a Liberian health official disclosed that a woman who had contracted the virus had died in an ambulance while waiting to be admitted to the other main treatment centre in Monrovia, which is also full.
De Cock said that because many families were reluctant to report cases to the authorities, the number of people infected with the virus could be several times higher than the figure so far recorded. Health officials needed to start actively searching them out before they passed it to others.
"This is an extremely severe situation and quite unprecedented. Much more active searching for cases is required, with health workers going into the community and doing outreach work."
The outbreak, he added, was expected to last for at least four to six months.
In Liberia - the most vulnerable nation because its health service was decimated during its 14-year civil war - people travelling from infected rural areas had spread Ebola into Monrovia, which now had an "independent, self-sustaining epidemic" of its own and was a "reservoir for infection".