Lassa Fever: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Lassa Fever?
An infectious disease doctor, a doctor who treats illnesses caused by germs, usually cares for people with Lassa fever. Lassa fever is a viral illness spread by a rat found in parts of West Africa. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Lassa fever?
Lassa fever is a severe viral illness that comes on quickly once someone is infected. It is caused by the Lassa virus. It is found in parts of West Africa, including Sierra Leone, Liberia, Guinea and Nigeria. Most people with Lassa fever have mild symptoms, but it can be deadly. In about 1 in 5 infections the disease becomes severe and can affect organs such as the liver, spleen and kidneys.
Symptoms
Signs and symptoms usually show up 1 to 3 weeks after a person is infected. Mild symptoms include:
- A slight fever.
- Feeling tired and weak.
- A headache.
About 8 in 10 infected people have mild symptoms and are not diagnosed. After a few days, a sore throat, muscle pain, chest pain, nausea, vomiting, diarrhea, cough and belly pain may follow.
Some people get more serious symptoms:
- Bleeding.
- Difficulty breathing.
- Swelling of the face.
- Pain in the chest, back and belly.
- Shock.
In later stages, shock, seizures, tremor, disorientation and coma may be seen. Lassa fever can lead to hearing loss. If a pregnant woman is infected, there is a high risk of miscarriage.
Causes and who gets it
Lassa fever is caused by infection with the Lassa virus, which is spread by rodents. The rats carry the virus in their urine and droppings, and they often live where food is stored. People mostly get sick by eating or breathing in the virus. It can also get into open cuts or sores. Breathing in air with infected urine or droppings can happen when cleaning or sweeping. People who live in neighboring countries are also at risk, because the rat lives throughout the region.
The virus can also spread through the body fluids of an infected person. People with Lassa fever are not contagious until after their symptoms begin. It does not spread through casual contact, such as hugging, shaking hands, or sitting near someone. In health care settings, it can spread when workers do not use proper protective equipment or sterilize equipment.
To lower the risk when in West Africa, keep away from rats. Store food in rat-proof containers and keep the home clean. Do not eat these rats.
How doctors diagnose it
Lassa fever can be hard to diagnose. Its symptoms vary and look like those of other diseases. Early on, it is hard to tell it apart from illnesses such as malaria, typhoid fever and yellow fever. Doctors confirm it with lab tests. One is a PCR test, which finds the virus's genetic material. Another is an antibody test called ELISA. Testing is done in a lab with a high level of safety measures.
Treatment
Early supportive care can improve the chance of survival. This means fluids and treatment of specific symptoms. The CDC says ribavirin, an antiviral drug, has been used to treat patients and works best when given soon after a person becomes sick. The WHO says no antiviral drug is approved for Lassa fever. It also says it is unclear how well ribavirin works. There is currently no licensed vaccine for Lassa fever.
When to see a doctor
If you have a fever after traveling in West Africa, see a doctor and say where you have been. Call 911 or go to the emergency room if you have bleeding that will not stop, difficulty breathing, a seizure, or sudden confusion.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care doctor can check a fever, ask about recent travel, and refer you to an infectious disease doctor or hospital when Lassa fever is possible.
Common questions
Is Lassa fever deadly?
Yes, Lassa fever can be deadly, but most people have mild symptoms. Among people in the hospital, about 15% die of the disease. Early supportive care improves the chance of survival.
How do people catch Lassa fever?
Most people catch Lassa fever from rats, not from other people. They get it from food or household items contaminated with rat urine or droppings.
Can Lassa fever spread from person to person?
Yes, it can, but not through casual contact. It spreads through blood, urine, stool or other body fluids of an infected person, mostly in health care settings. Hugging, shaking hands, or sitting near someone does not spread it.
Does Lassa fever cause hearing loss?
Yes, Lassa fever can cause hearing loss, even in mild cases. In many cases, the hearing loss is permanent.
Sources
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
