The World Health Organisation (WHO) has raised concern over Lassa fever deaths in Nigeria.

It warned that rising infections and fatalities since late 2025 remain a serious public health threat to the nation. 

The organisation said the situation remains worrisome due to the endemic nature of the disease, which continues to affect residents in the southern and northern parts of the country. 

Speaking on Wednesday at a press briefing on regional health priorities and progress updates, the WHO’s Director of Health Emergencies, Marie Rouslyn Belisee, said organisation was partnering the Nigerian government in addressing the fight against the outbreak. 

According to Ms Belisee, Nigeria has recorded 685 confirmed cases of Lassa fever since November 2025, in addition to more than 4,000 suspected cases being monitored across affected communities in the country. 

She stated that the outbreak had resulted in deaths within the period under review, describing the figure as alarming, particularly given the increasing number of infections among healthcare workers.

Ms Belizaire added that 42 health workers had also been infected while responding to the outbreak, with five deaths of the medical professionals recorded. 

“The Lassa fever is concerning in Nigeria. Since November 2025 till date. The country has notified 685 confirmed cases. We also have more than 4000 suspected cases. Among those cases, the country notified 170 deaths and that is also very concerning not only for the population but also the health care workers. 42 healthcare workers have been infected. 

“And five have lost their lives while serving the population. Nigeria continues to experience Lassa fever outbreak because it is an endemic disease. We have to know what it is behind Lassa fever,” she said. 

She noted that Lassa fever remains endemic in Nigeria and transmitted mainly through contact with food or household items contaminated by urine or faeces of infected ‘multimammate rats,’ widespread in both rural and urban areas.

“The disease continues to persist because the underlying drivers have not been sufficiently addressed at community and national levels,” she said, 

Pointing to poor environmental sanitation and continued exposure to rodent-infested environments as key factors sustaining transmission, Ms Belisee explained that recurring outbreaks across the country highlight gaps in prevention and community awareness.

She affirmed that stronger grassroots interventions were needed to curb spread despite the strong interventions from the international organisation. 

The WHO official referenced examples from other African countries, including Zambia, where community-driven innovations such as rat-trapping initiatives were introduced to reduce transmission risks.

“I was in Zambia and I saw how the country is coming up with innovations on how to deal with the disease. They show in the conference how they are putting on trap for rat in their communities that was really innovative,” she stated. 

Ms Belizaire said WHO was working closely with the Nigeria Centre for Disease Control and Prevention (NCDC) to strengthen surveillance systems, improve early detection of cases, and ensure timely access to treatment for affected persons.

She stated, “We work together with the NCDC for surveillance and also to gain access to those infected to care. We give free treatment to those affected in the community. We also give access to information. We support the country to put in place community support measures.”

She added that the health organisation was supporting risk communication and community engagement efforts, as well as providing treatment support to reduce fatalities in affected areas.

However, Ms Belisee noted that there were signs of improvement, with a gradual decline in transmission trends in recent weeks in the country. 

“So far it is concerning because we have 36 of our local community that are reporting the case (Lassa fever) but we will continue to work. However, We also have progress because the epidemic is decreasing and we will continue to work until the end of the outbreak and to maintain the threshold level is very low in Nigeria,” she added. 

The WHO urged sustained national and community-level interventions to ensure continued reduction in cases and prevent future outbreaks, stressing the need to maintain surveillance and keep infection levels at a minimal threshold nationwide.

Last week, the NCDC said that Lassa fever deaths had risen in 2026. 

The NCDC in its Epidemiological week 13 report in Abuja confirmed that 167 deaths were recorded in the year under the review. 

The report noted that 26 new confirmed cases were recorded in week 13, a decrease from 51 cases reported in the previous week.

The cases were reported across seven states viz Edo, Bauchi, Ondo, Taraba, Ebonyi, Benue and Kaduna.

The NCDC noted on Wednesday that Nigeria was recording a rising Lassa fever fatality rate despite a decline in weekly confirmed cases.

It noted that the development raised fresh concerns over the disease management nationwide.

In its Epidemiological Week 14 report for 2026 on Wednesday, the NCDC confirmed that cases dropped from 26 in the previous week to 22, while the case fatality rate rose significantly.