All schools in Nigeria have been ordered to remain shut until 13 October as part of measures to prevent the spread of the deadly Ebola virus.
The new academic year was due to start on Monday.
But the education minister ordered the closures to allow staff to be trained on how to handle suspected Ebola cases.
Five people have died of Ebola in Nigeria. The West Africa outbreak has centred on Guinea, Liberia and Sierra Leone, killing more than 1,400 people.
It is the largest ever outbreak and has infected an estimated 2,615 people. About half of those infected have died.
“There are many other diseases right now not being attended to because Ebola has overstretched the capacity of the health sector” Donald Kaberuka AFDB president
It spread to Nigeria – Africa’s most populous country – in July, when a man infected with Ebola flew from Liberia to Lagos.
The head of the African Development Bank (AFDB), Donald Kaberuka, has called on airline companies to restart their services to the worst-affected countries.
Several African countries and airlines have banned flights to Guinea, Liberia and Sierra Leone despite World Health Organization (WHO) advice that travel bans do not work.
Air France has now announced it is suspending flights to Sierra Leone from Thursday, following a request by the French government.
The virus is not airborne and is spread between humans through direct contact with infected bodily fluids.
“It is very important that as you combat Ebola, we also continue to ensure that ordinary economic activity is not disputed,” Mr Kaberuka told BBC Africa on a visit to Sierra Leone.
The Nigerian government says it hopes its efforts to contain the virus are working, as there is only one confirmed case of Ebola remaining.
“All state ministries of education are to immediately organise and ensure that at least two staff in each school, both private and public, are trained by appropriate health workers,” said Education Minister Ibrahim Shekarau.
Mr Kaberuka said the AFDB had signed an agreement with the WHO to quickly release $60m (£36m) of funds to help with the immediate fight against Ebola.
He described the situation as “cataclysmic” as many health workers were being infected with Ebola.
“It is decimating the health sector,” he said.
“There are many other diseases right now not being attended to because Ebola has overstretched the capacity of the health sector.”
On Tuesday, the WHO said the “unprecedented” number of doctors and nurses infected was due to a shortage of protective equipment and staff.
Only one or two doctors are available for 100,000 patients in some of the affected countries.
The bank chief said after the Ebola emergency was over, it was important that these countries health systems were strengthened, which the AFDB could do through budget support.
Meanwhile, a WHO epidemiologist from Senegal who contracted Ebola while working in Sierra Leone has been flown to Hamburg in Germany for treatment.
He had been working at an Ebola testing centre in Kailahun, one of the worst-affected districts in eastern Sierra Leone which is currently under blockade.
The WHO says the laboratory in Kailahun has been temporarily closed.
There have been 392 Ebola deaths in Sierra Leone, according to the latest UN figures released on 22 August.