The Nigeria Centre for Disease Control (NCDC) has activated the national multi-sectoral and multi-disciplinary Lassa fever Emergency Operations Centre (EOC).
A statement on Wednesday said this was in response to the outbreak in some parts of the country.
The NCDC disclosed that it conducted a joint risk assessment with partners and sister agencies.
As of Sunday, 115 cases with 26 deaths (fatality ratio of 22.6 per cent) had been reported from 30 local government areas across 11 states.
Weeks one and two of the current wave show the highest number of cases recorded in the last four years for the same period.
The disease is an acute viral hemorrhagic illness transmitted through contact with food or household items contaminated by rodents.
Human transmission can also occur, particularly in a hospital environment with inadequate infection control measures.
Lassa fever is usually recorded in West Africa during the dry season, mostly between November and May.