Lassa Fever Public Health Advisory

Tuesday, December 14, 2021

14 December 2021 | Abuja – Lassa Fever Public Health Advisory

Lassa fever remains a major public health challenge in West Africa with Nigeria bearing the highest burden. Lassa fever occurs throughout the year, but more cases are seen during the dry season i.e., November through May.

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) but other rodents have also been identified as carriers of the virus. The virus is spread through:

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

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

3. Ingesting foods contaminated with urine, faeces, saliva or blood of infected rats.

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

Lassa fever initially presents like any other febrile illness such as malaria. Its symptoms include fever, headache, sore throat, general body weakness, cough, nausea, vomiting, diarrhoea, muscle pains, chest pain, and in severe cases, unexplainable bleeding from ears, eyes, nose, mouth and other body openings. The time between an infection and appearance of symptoms of the disease is 6 to 21 days. Early diagnosis and treatment increase the chances of survival.

People most at risk are:

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

2. People living in rat infested environments

3. People who consume potentially contaminated food stuff especially those left open overnight or dried outside in the open

4. People who handle or process rodents for consumption

5. People who do not perform hand hygiene when appropriate

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

7. Health care workers including:

a. Doctors, nurses and other health workers providing direct patient care in the absence of standard precautions.

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

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

d. Medical or support staff who prepare and or handle dead bodies without appropriate precautions

To reduce the risk of Lassa fever, the Nigeria Centre for Disease Control (NCDC) offers the following advice:

1. Keep your environment clean at all times

2. Block all holes in your house to prevent entry of rats.

3. Cover your dustbins and dispose refuse properly. Communities should setup dump sites very far from their homes to reduce the chances of having rodents within homes

4. Store foodstuff like rice, garri, beans, corn/maize etc. containers which are well covered with tight fitting lids

5. Avoid drying food stuff outside on the floor, roadside where it will be exposed to contamination

6. Avoid bush burning which can lead to displacement of rats from bushes to human dwellings

7. Eliminate rats in homes and communities by setting rat traps and other means available

8. Practice good hand hygiene by frequent washing hands with soap under running water /or use of hand sanitizers when appropriate

9. Visit the nearest health facility if you notice any of the signs and symptoms of Lassa fever as mentioned earlier, avoid self-medication

10. Healthcare workers are advised to always practice standard precautions: i.e., wear gloves and other appropriate personal protective equipment while handling patients or providing care to an ill patient/relative.

11. 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.

Any febrile illness that has not responded to 48 hours use of anti-malaria or antibiotics should raise an index of suspicion for Lassa fever! Please if your healthcare worker suspects Lassa fever, advise him or her to contact your local government Disease Surveillance and Notification Officer for immediate access to healthcare. This is essential because early treatment for cases and preventive treatment for high risk contacts appear to be more effective when started very early.

About the NCDC

The Nigeria Centre for Disease Control is the country’s national public health institute, with the mandate to lead the preparedness, detection and response to infectious disease outbreaks and public health emergencies. The Bill for an Act to establish NCDC was signed into law in November 2018, by President Muhammadu Buhari. The mission for the NCDC (2017-2021) is ‘To protect the health of Nigerians through evidence-based prevention, integrated disease surveillance and response activities, using a One Health approach, guided by research and led by a skilled workforce’.


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


Dr Ifedayo Adetifa

DG, Nigeria Centre for Disease Control

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