Five states have accounted for 86 per cent of Nigeria’s 1,000 confirmed Lassa fever cases recorded so far in 2026, with Bauchi, Ondo, Taraba, Benue and Edo continuing to bear the heaviest burden of the disease.
The latest figures from the Nigeria Centre for Disease Control and Prevention (NCDC) show that Lassa fever has been reported across 23 states and 116 local government areas since the beginning of the year.
According to the agency’s Lassa Fever Situation Report for epidemiological Week 30, covering July 20 to 26, Nigeria recorded 17 new confirmed infections during the week, pushing the cumulative number of cases to 1,000.
The outbreak has also claimed 237 lives, translating to a case fatality rate of 23.7 per cent.
Although the number of new infections recorded in Week 30 declined compared with the previous week, when 20 cases were confirmed, the overall disease burden continued to rise.
The cumulative number of confirmed cases increased from 983 in Week 29 to 1,000 in Week 30, while the death toll rose from 231 to 237.
The case fatality rate also edged upwards from 23.5 per cent to 23.7 per cent.
Four states record fresh infections
The NCDC report showed that the 17 new cases recorded during the latest reporting week came from four states — Ondo, Bauchi, Edo and Benue.
The continued emergence of new infections in states that already account for a significant proportion of the national caseload highlights the persistent transmission of Lassa fever in some parts of the country.
Bauchi, Ondo, Taraba, Benue and Edo have consistently featured among the states most affected by the disease, accounting collectively for the vast majority of confirmed infections recorded in 2026.
The concentration of cases in the five states also underscores the uneven geographical distribution of Lassa fever in Nigeria and places increased pressure on health authorities in affected areas to maintain surveillance and strengthen early detection.
For the states at the centre of the outbreak, sustained access to diagnostic services, effective case management and infection-prevention measures remains critical to limiting further transmission and reducing deaths.
Young adults among most affected
The latest epidemiological data also indicate that Lassa fever continues to affect a predominantly young adult population.
People between the ages of 21 and 30 years were identified as the most affected age group, pointing to a significant burden among Nigerians in their economically active years.
The pattern reinforces the need for continued public awareness and preventive measures, particularly in communities where the disease is endemic.
Healthcare workers face occupational risk
The outbreak is also posing a continuing threat to healthcare workers involved in the treatment of infected patients.
The NCDC reported one new Lassa fever infection among healthcare workers during Week 30, compared with no new healthcare worker infection in the preceding week.
The development highlights the occupational risks faced by doctors, nurses, laboratory personnel, caregivers and other health workers who may come into contact with patients whose infections have not yet been diagnosed.
Because Lassa fever can be transmitted through contact with the blood and other body fluids of infected people, strict infection-prevention and control measures remain essential in healthcare settings.
Early recognition and diagnosis are particularly important because patients may initially present with symptoms that resemble other common illnesses, potentially increasing the risk of delayed treatment and exposure among healthcare personnel.
How Lassa fever spreads
Lassa fever is an acute viral illness that is endemic in parts of West Africa, including Nigeria. The disease remains a recurring public-health challenge, particularly during periods when transmission increases in affected communities.
The primary route of transmission to humans is through contact with food or household items contaminated by the urine or faeces of infected multimammate rats, which are the principal reservoir of the virus.
Human-to-human transmission can also occur, particularly through direct contact with the blood or body fluids of infected individuals.
This makes healthcare facilities a critical point for infection prevention, especially where patients present with symptoms that could be associated with Lassa fever.
Surveillance remains critical
With confirmed infections now reaching 1,000 in 2026, the latest figures highlight the importance of sustained surveillance across affected and neighbouring states.
While the decline in weekly cases from 20 to 17 may offer some indication of a reduction in new infections during the reporting period, the rise in cumulative cases and deaths shows that the outbreak remains a significant public-health concern.
Health authorities will therefore need to maintain vigilance, particularly in the five states responsible for the overwhelming share of reported infections, while strengthening early detection, laboratory confirmation, treatment, contact tracing and infection-prevention measures.
The continued infection of healthcare workers also serves as a reminder that controlling Lassa fever requires not only community-level prevention but also robust protection for those on the frontline of the response.