Lassa Fever

  • Medical Author:

    Sandra Gonzalez Gompf, MD, FACP is a U.S. board-certified Infectious Disease subspecialist. Dr. Gompf received a Bachelor of Science from the University of Miami, and a Medical Degree from the University of South Florida. Dr. Gompf completed residency training in Internal Medicine at the University of South Florida followed by subspecialty fellowship training there in Infectious Diseases under the directorship of Dr. John T. Sinnott, IV.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

Lassa Fever Treatment & Medication

Ribavirin (Rebetol, Copegus, Ribasphere, RibaPak, Moderiba)

Ribavirin is an antiviral drug. It is used in combination with interferon for the treatment of chronic hepatitis C. Although the exact mechanism of its action is unknown, it is thought to interfere with the production and/or action of viral DNA and RNA which are critical to the survival and multiplication of the virus.

Lassa fever facts

  • Lassa fever is one of the hemorrhagic fever viruses, like Ebola virus, Marburg virus, and others.
  • Like Ebola virus, Lassa fever occurs primarily in West Africa.
  • Unlike Ebola virus, Lassa fever is not as contagious person to person, nor as deadly.
  • Lassa virus is transmitted from rodents to humans.

What is Lassa fever?

Lassa fever is a hemorrhagic fever virus from the family Arenaviridae. It is an acute viral illness lasting one to four weeks, and it occurs in West Africa and some areas beyond.

What is the history of Lassa fever?

Lassa fever was first described in the 1950s, and the viral particle was identified in 1969 from three missionary nurses who died in Lassa, Nigeria, after caring for an infected obstetrical patient. Lassa fever is one of the hemorrhagic fever viruses, occurring in West Africa in similar areas as Ebola virus. There are 100,000-300,000 cases of Lassa fever each year in the world, causing an estimated 5,000 deaths and about 10%-15% of admissions to hospitals in Sierra Leone and Liberia. Deaths are especially common in children. Case fatality is 1% in general, although severe cases have a case fatality of 15%.

Lassa fever has rarely been diagnosed in the U.S. each year, largely as a result of international travel or immigration. A case was diagnosed in May 2015 in New Jersey in a patient traveling from Liberia, the sixth active case documented in returning travelers to the U.S. since 1969.

What are causes and risk factors for Lassa fever?

Lassa fever virus is an Arenavirus that is mainly a zoonosis (a disease spread to humans from animals). It is spread to people through contact with household items or food contaminated with the rodent droppings or urine of infected multimammate rats (Mastomys natalensis). These rodents live throughout West Africa in homes, and they can shed this virus without being ill. People most become infected through inhaling aerosols in air contaminated with rodent excretions, swallowing the virus in food or contaminated utensils (or multimammate rats eaten as food), or through open wounds. Lassa fever virus is believed to be endemic (always present) in Benin, Guinea, Sierra Leone, Liberia, and some parts of Nigeria. It has also been detected in the Ivory Coast, Ghana, Burkina Faso, Mali, Senegal, Gambia, and Central African Republic.

Travelers to West Africa, especially those staying in homes or areas of poor sanitation or crowding, or health-care and laboratory professionals serving in affected areas, are most at risk.

Those at highest risk for serious complications and death are pregnant women in their third trimester. Stillbirth or fetal loss occurs in 95% of pregnancies.

Medically Reviewed by a Doctor on 10/27/2016

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