Nigeria was on alert against the possible spread of Ebola on Saturday, a day after the first confirmed death from the virus in Lagos, Africa’s biggest city and the country’s financial capital.

The health ministry said Friday that a 40-year-old Liberian man died at a private hospital in Lagos from the disease, which has now killed more than 650 people in four west African countries since January — the deadliest outbreak in history.

The victim, who worked for the Liberian government, collapsed at Lagos international airport after arriving on a flight from Monrovia via the Togolese capital Lome on Tuesday, according to the Nigerian government.

He did not come into contact with the public in Lagos other than health workers before being isolated at the hospital, they added. The World Health Organization (WHO) said today that efforts were being made to track down people the victim may have come into contact with on his journey from the Liberian capital.

“Contact tracing under way — Liberia, Nigeria, Togo. WHO deployed staff to Nigeria to help w/ this & safe handling of remains,” the global health body’s African region said on its Twitter account @WHOAFRO.

Nigerian Health Minister Onyebuchi Chukwu had previously said all passengers who travelled with the victim on the Togo-based carrier ASKY from Lome had been traced.

Meanwhile an emergency operations centre has been set up, coordinated by the Nigeria Centre for Disease Control (CDC), and all hospitals have been equipped to handle emergencies and suspected cases, the minister added. Borders have not been closed but health specialists have been deployed to all sea ports and international airports to identify any passengers displaying symptoms associated with Ebola.

In Lagos, Yewande Adeshina, the special adviser on public health to the Lagos State governor, said: “We have taken delivery of 30 personal protective equipment (sets) from the federal ministry of health and they have promised to give an additional 220 for our medical personnel to protect them from any risks… “We are also reaching out to private clinics, hospitals and health facilities in the state to promptly report any suspected case to the authorities.”

Information Minister Labaran Maku said a radio and television public awareness campaign about Ebola has been running for several months on state media and would continue.