Nigerian authorities have put health workers on red alert following the resurgence of Ebola epidemic in Guinea.
Health Minister Osagie Ehanire said they would monitor all entry points to pick out any suspected cases, local media reports.
The minister said they were following developments in Guinea with concern.
Guinea has registered a fourth death linked to the disease.
The 2014-2016 Ebola outbreak in West Africa left more than 11,000 people dead.