Lassa fever is one of Nigeria's most serious public health threats, yet most people don't know the warning signs until it's too late. Whether you're a concerned parent, a healthcare worker, or simply someone who wants to protect their family, this guide covers everything you need to know: what Lassa fever is, how it spreads, how to recognise its symptoms, and exactly what to do if you suspect infection.

What Is Lassa Fever?

Lassa fever is an acute viral haemorrhagic illness caused by the Lassa virus, a member of the Arenaviridae family. It was first identified in 1969 in Lassa, Borno State, Nigeria — and the country remains one of the most affected in the world.

The disease is endemic in West Africa, particularly in Nigeria, Sierra Leone, Guinea, and Liberia. In Nigeria, outbreaks occur year-round but peak between October and March — the dry season — when mastomys rats, the primary animal reservoir, move closer to human settlements in search of food.
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📌 Key Fact: About 80% of people infected with the Lassa virus have no symptoms at all. However, 1 in 5 infections result in severe, life-threatening disease affecting the liver, spleen, and kidneys.

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How Does Lassa Fever Spread? (Modes of Transmission)

Understanding how Lassa fever spreads is the first step to protecting yourself and your community.

1. Direct Contact With Infected Rodents

The Lassa virus is carried by the multimammate rat (Mastomys natalensis), a common rodent in Nigeria. Humans become infected through:

  • Contact with rat urine, faeces, or saliva — directly or through contaminated surfaces
  • Eating or handling infected rats (a food source in some regions)
  • Inhaling dust or aerosols contaminated with rat excretions

2. Ingestion of Contaminated Food

Food stored in open spaces where rats have access is a major transmission route. Grains, rice, groundnuts, and other staple foods can easily become contaminated. Always store food in sealed, rodent-proof containers.

3. Person-to-Person Infection

Although less common, Lassa fever can spread between people through direct contact with blood, urine, faeces, vomit, or other bodily fluids of an infected person. Healthcare workers face particular risk if proper infection prevention and control (IPC) measures are not in place.

4. Laboratory Exposure

Healthcare and laboratory staff handling specimens from Lassa fever patients must follow strict biosafety protocols. Accidental needle-stick injuries or improper sample handling can cause infection.

⚠️ Important: Lassa fever does NOT spread through casual contact like hugging, shaking hands, or being in the same room as someone who is infected, provided there is no exposure to bodily fluids.
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Symptoms of Lassa Fever: What to Watch For

Symptoms typically appear 6 to 21 days after exposure to the Lassa virus. The illness progresses through stages — from mild flu-like symptoms to severe haemorrhagic complications if untreated.

Early Symptoms (Days 1–3)

  • Fever (gradual onset)
  • General weakness and fatigue
  • Headache
  • Sore throat
  • Muscle pain (myalgia)
  • Chest pain
  • Nausea and vomiting
  • Cough

Severe Symptoms (Days 4–7 and Beyond)

  • Bleeding from body orifices — mouth, nose (nostrils), ears, vagina, anus
  • Swelling of the face
  • Pain in the chest, back, or abdomen
  • Shock and low blood pressure
  • Hearing loss (a common complication even in recovered patients)
  • Seizures
  • Coma
🔴 Warning: Symptoms may vary from mild to severe. In the worst cases, Lassa fever progresses to multi-organ failure and death within 14 days of illness onset. Seek immediate medical care if you develop fever alongside any of the above symptoms, especially bleeding.

How Is Lassa Fever Diagnosed?

Because early Lassa fever symptoms overlap with many other illnesses — including malaria, typhoid, and other viral fevers — laboratory testing is essential for definitive diagnosis. Clinical diagnosis alone is unreliable.

Diagnosis is confirmed through:

  • Reverse transcription polymerase chain reaction (RT-PCR) — the gold standard test, detecting the Lassa virus RNA in blood or tissue samples
  • Enzyme-linked immunosorbent assay (ELISA) — detects Lassa-specific antibodies (IgM and IgG) or antigens
  • Virus isolation — only performed in Biosafety Level 4 (BSL-4) laboratories

How to Get Tested for Lassa Fever in Nigeria

If you suspect you or someone close to you may have been exposed to Lassa fever, getting tested quickly is critical. Early diagnosis dramatically improves survival outcomes. Here’s how to access Lassa fever testing in Nigeria.

1. Visit a Government-Approved Testing Facility

The Nigeria Centre for Disease Control (NCDC) coordinates Lassa fever surveillance and maintains a network of approved diagnostic laboratories across the country. Key testing centres include:

  • Irrua Specialist Teaching Hospital (ISTH), Edo State — one of Nigeria’s foremost Lassa fever treatment and research centres
  • Federal Medical Centre, Owo, Ondo State
  • NCDC National Reference Laboratory, Abuja
  • Lagos University Teaching Hospital (LUTH) and other state teaching hospitals with virology departments

2. Seek Care Through EHA Clinics

EHA Clinics in Abuja, Lagos, and Kano can assess your symptoms, take a detailed exposure history, and rapidly refer you to appropriate testing facilities. Our clinical teams are trained in Lassa fever recognition and follow strict infection prevention protocols. If you are concerned, do not delay — contact us immediately.

3. What to Expect During Testing

When you arrive at a clinic or hospital with suspected Lassa fever, you should expect the following steps:

  • Triage and isolation: You will be separated from other patients immediately to prevent potential spread
  • Clinical assessment: A doctor will take your full symptom and exposure history
  • Blood sample collection: A blood sample is taken under strict biosafety conditions and sent to an approved laboratory for RT-PCR or ELISA testing
  • Results and next steps: Results are typically available within 24–72 hours. If positive, treatment and contact tracing will begin immediately
📍 Important: Always call ahead before visiting any clinic if you suspect Lassa fever. Informing the facility in advance allows them to prepare appropriate isolation measures and protect both you and other patients.


There is currently no approved vaccine for Lassa fever, but treatment is available and most effective when started early.

Antiviral Medications

Ribavirin, an antiviral drug, is the primary treatment for Lassa fever. It is most effective when administered within the first six days of illness. Ribavirin significantly reduces mortality when given early and in adequate doses.

Supportive Care

Alongside antiviral treatment, patients receive intensive supportive care including:

  • Intravenous fluids and electrolyte management
  • Blood pressure support
  • Oxygen therapy
  • Treatment of secondary infections
  • Monitoring of organ function

Isolation Procedures

All confirmed or suspected Lassa fever patients must be isolated to prevent nosocomial (healthcare-associated) spread. Healthcare workers must use full personal protective equipment (PPE), including gloves, gowns, eye protection, and N95 respirators or equivalent.

💡 Pro Tip: Early presentation to a healthcare facility dramatically improves survival. Do not wait for symptoms to worsen — if you suspect Lassa fever exposure, seek care immediately and inform the facility upon arrival.

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How to Protect Yourself and Your Family: Preventive Measures

1. Practise Proper Sanitation

  • Keep your home and environment clean and free of rodents
  • Block holes, cracks, and entry points that rats can use to enter your home
  • Dispose of rubbish properly and regularly
  • Avoid leaving food waste exposed

2. Avoid Contact With Rodents

  • Do not handle rats — dead or alive — without protective gear
  • Use rodenticide (rat poison) and traps safely
  • Discourage children from playing with rodents

3. Practise Safe Food Habits

  • Store grains, rice, and all food items in sealed, rodent-proof containers
  • Avoid eating or selling smoked, dried rats — a known high-risk food in some communities
  • Wash all food thoroughly before cooking
  • Cook food to safe temperatures to kill pathogens

4. Follow Infection Prevention in Healthcare Settings

  • Always use gloves and PPE when handling patients or laboratory specimens
  • Follow standard precautions for all patients
  • Immediately report suspected cases to your facility's IPC team
  • Ensure proper disposal of sharps and biohazardous waste

5. Community Education and Awareness

One of the most powerful tools against Lassa fever is knowledge. Share this information with your family, neighbours, and community. Early recognition of symptoms and prompt care-seeking behaviour saves lives.

Who Is Most at Risk of Lassa Fever in Nigeria?

While anyone can contract Lassa fever, certain groups face significantly higher risk:

  • People living in or travelling to endemic areas in Nigeria (particularly Edo, Ondo, Ebonyi, Bauchi, Kogi, and Plateau states)
  • Healthcare workers without proper PPE
  • People in households with rodent infestations
  • Communities that store food without rodent-proof containers
  • Laboratory workers handling samples from potentially infected patients
  • People in low-resource settings with limited sanitation

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Frequently Asked Questions About Lassa Fever

Question

Answer

Is Lassa fever curable?

Yes. With early antiviral treatment (ribavirin) and supportive care, most patients recover fully. Early detection is critical.

Can Lassa fever spread through the air?

Not through casual airborne contact. It spreads via direct contact with bodily fluids or exposure to contaminated rat excretions.

Is there a vaccine for Lassa fever?

No approved vaccine exists yet. Prevention through rodent control, sanitation, and food safety remains the primary strategy.

How long does Lassa fever last?

Illness typically lasts 1–4 weeks. Severe cases can progress rapidly. Hearing loss may persist after recovery.

Can I travel to endemic areas?

Yes, with precautions. Avoid rodent contact, practise food safety, and seek immediate care if fever develops within 21 days of travel.

Where can I get tested in Nigeria?

EHA Clinics in Abuja, Lagos, and Kano can guide you. The NCDC also maintains a network of Lassa fever diagnostic facilities.
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When Should You Seek Medical Help?

Seek medical attention immediately if you experience:

  • Fever lasting more than 2–3 days, especially combined with weakness, sore throat, or muscle pain
  • Any unexplained bleeding from the mouth, nose, ears, or other orifices
  • Recent contact with rodents or their droppings
  • Recent travel to Lassa-endemic states in Nigeria
  • Exposure to a confirmed or suspected Lassa fever patient

When you arrive at the clinic or hospital, inform the triage staff immediately about your symptoms and any potential exposure. This allows them to implement isolation and protect other patients and staff.

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Concerned About Your Health?

EHA Clinics offers expert consultations, diagnostics, and preventive care across Nigeria. Don't wait — your health matters.

📞 Call: 0909-399-5002 or 0800-342-254-6427

🌐 www.eha.ng  📍 Abuja | Lagos | Kano

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