Lassa Fever Public Health Advisory

Saturday, December 16, 2023

Every year, the Federal Government of Nigeria, through the Federal Ministry of Health and Social Welfare and the Nigeria Centre for Disease Control and Prevention (NCDC’s) National Lassa Fever Technical Working Group (TWG) leads on efforts to prevent, detect, and respond to cases of Lassa fever across the country.

We have continued to record a steady increase in states reporting Lassa fever for reasons not limited to improved surveillance, better community awareness, environmental degradation from climate change and other deleterious human activities in the environment. In 2021, 510 confirmed cases were reported across 17 states and 68 Local Government Areas (LGAs). Whereas in 2022, Nigeria reported 1067 confirmed cases across 27 States and 112 LGAs. In 2023 alone, 28 states and 114 LGAs have reported confirmed cases of Lassa fever and as of 3rd December 2023, there have been 8542 suspected cases, 1170 confirmed cases, and 200 deaths (case fatality rate of 17.1%) suggesting 2023 may witness record numbers of cases.

Annual outbreaks of Lassa fever also involve the infection and death of healthcare workers. This loss of life is not just a statistic but a significant loss of a loved family member, a spouse, a parent, and often seasoned healthcare worker and team member. This exacerbates the challenge of insufficient human resources for health in the country.

Now that the dry season is here, the NCDC’s Lassa Fever TWG has implemented strategic measures to enhance coordination, collaboration, and communication, enhancing preparedness and readiness for potential surges in Lassa fever cases. These measures include:

Conducting biweekly National TWG meetings to improve preparedness, readiness, and response activities for control and management of Lassa fever using a One Health approach.

Joint alert with the cerebrospinal meningitis (CSM) TWG was sent to States to guide state -level preparedness, readiness, and response activities in Lassa fever and CSM during this season that both diseases share.

Capacity building of some healthcare workers across all the geopolitical zones on Lassa fever preparedness, readiness, and response through the pilot Lassa fever clinical management fellowship.

Conducting a bi-weekly Lassa fever webinar series on topics covering the different pillars of the TWG (case management, surveillance, IPC, Risk communication, logistics, etc.) to get all actors in control and management of Lassa fever ready for the predicted surge in confirmed case numbers.

Prepositioning and distribution of medical supplies for case management, infection prevention, and control, laboratory diagnosis, etc. in all Lassa fever treatment centres in the country.

An update of the national incident action plan (IAP) to take onboard lessons from the last outbreak and findings from the recently concluded surge preparedness workshop.

Publishing weekly situation reports for Lassa fever in Nigeria to guide decision-making and foster further collaboration across different sectors.

About Lassa Fever

Lassa fever is an acute viral haemorrhagic fever (VHF) caused by the Lassa virus. The natural reservoir for the virus is the Mastomys natalensis rodent (commonly known as the multimammate rat or the African rat). Other rodents can also be carriers of the virus.

The virus spreads through:

• Direct contact with urine, faeces, saliva, or blood of infected rats.

• Contact with objects, household items, and surfaces contaminated with the urine, faeces, saliva, or blood of infected rats.

• Consuming food or water contaminated with the urine, faeces, saliva, or blood of infected rats.

• Person-to-person transmission can also occur through direct contact with blood, urine, faeces, vomitus, and other body fluids of an infected person.

Lassa fever initially presents like other common illnesses accompanied by a fever, such as malaria. Other symptoms include headache, general body weakness, cough, nausea, vomiting, diarrhoea, muscle pains, chest pain, sore throat, and, in severe cases, bleeding from ears, eyes, nose, mouth, and other body openings. The time between infection and the appearance of symptoms of the disease is 3 to 21 days. Early diagnosis and treatment of the diseases greatly increase the chances of patient survival.

People most at risk for Lassa fever are:

• People of all age groups who come in contact with the urine, faeces, saliva, or blood of infected rats.

• People living in rat-infested environments.

• People who consume potentially contaminated foodstuff, especially those left open overnight or dried outside in the open.

• People who handle or process rodents for consumption.

• People who do not perform hand hygiene at appropriate times.

• Caretakers of infected persons with poor infection prevention and control measures.

Healthcare workers including:

• Doctors, nurses, and other health workers who provide direct patient care in the absence of standard precautions.

• Hospital staff who clean and disinfect contaminated surfaces, materials, and supplies without adequate protective gear.

• Laboratory staff who handle blood samples of suspected Lassa fever patients without appropriate precautions.

• Persons who prepare and/or handle bodies of deceased Lassa fever cases without appropriate precautions.

The NCDC-led National Lassa Fever TWG offers the following advice to reduce the risk of Lassa fever infection:


• Always keep your environment clean.

• Block all holes in your house to prevent the entry of rats and other rodents.

• Cover your dustbins and dispose of refuse properly. Communities should set up dump sites far from their homes to reduce the chances of the entry of rodents into their homes.

• Safely store food items such as rice, garri, beans, corn/maize, etc., in tightly sealed or well-covered containers.

• Avoid drying food stuff outside on the ground or roadside, where it is at risk of contamination.

• Discourage bush burning. This destroys the homes and food sources of rodents and drives them to migrate from the bushes to human residences to find food.

• Eliminate rats in homes and communities by setting rat traps and other appropriate and safe means.

• Practice good personal and hand hygiene by frequently washing hands with soap under running water or using hand sanitisers when necessary.

• Visit the nearest health facility if you notice any of the signs and symptoms associated with Lassa fever mentioned earlier or call the State Ministry of Health hotline and 6232 (NCDC). This is essential because early identification and treatment of cases appear to be more effective and can save lives.

• Avoid self-medication to ensure proper diagnosis and early treatment.


• Healthcare workers are advised to always practice standard infection prevention and control practices, i.e., using gloves and other appropriate personal protective equipment while handling patients or providing care for an ill patient.

• Healthcare workers should maintain a high index of suspicion for Lassa fever, i.e., be vigilant and consider a diagnosis of Lassa fever when seeing patients presenting with febrile illness.

• Healthcare providers should report all suspected cases of Lassa fever to their local government Disease Surveillance and Notification Officer to ensure prompt diagnosis, referral, and early commencement of public health actions.

About NCDC

The Nigeria Centre for Disease Control and Prevention (NCDC) is the country's national public health institute, with the mandate to lead the preparedness, detection, and response to public health emergencies. The Bill for an Act to establish NCDC was signed into law in November 2018, by President Muhammadu Buhari. The mission of the NCDC is 'To protect the health of Nigerians through evidence-based prevention, integrated disease surveillance and response, using a One Health approach, guided by research and led by skilled workforce'.


NCDC Toll-free Number: 6232 | SMS: 08099555577 | WhatsApp: 07087110839 Twitter: @NCDCGov | Facebook: @NCDCgov | Instagram: @NCDCgov | NCDC Media Releases


Dr Ifedayo Adetifa

Director General

Nigeria Centre for Disease Control and Prevention.

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