Health officials in Cameroon say they have detected two suspected cases of the Marburg virus close to the border with Equatorial Guinea.
Neither of the pair had travelled across the frontier.
Officials are now trying to track down everyone they have been in contact with.
The World Health Organization has sent more contact tracing teams to eastern Equatorial Guinea to try to contain the spread of the virus.
Nine people are thought to have died from the disease in Equatorial Guinea where there are a further 16 suspected cases.
Restrictions on movements had already been in force in Cameroon’s southern border area.
