lassa fever

Onset of symptoms is typically 7 to 21 days after exposure.{{cite web |title=About Lassa Fever |url=https://www.cdc.gov/lassa-fever/about/index.html |website=CDC |access-date=7 February 2025 |language=en-us |date=31 January 2025}} These mild symptoms may include fever, tiredness, weakness, and headache. In 20% of people more severe symptoms such as bleeding gums, breathing problems, vomiting, chest pain, or dangerously low blood pressure may occur. Long term complications may include hearing loss. In women who are pregnant, miscarriage may occur with a likelihood of 95%. Lassa fever can be difficult to distinguish clinically from other viral hemorrhagic fevers, such as Ebola virus disease. A combination of pharyngitis, pain behind the sternum, presence of excess protein in the urine and fever can indicate Lassa fever with higher specificity.{{cite journal |vauthors=McCormick JB, King IJ, Webb PA, Johnson KM, O'Sullivan R, Smith ES, Trippel S, Tong TC |title=A Case-Control Study of the Clinical Diagnosis and Course of Lassa Fever |journal=The Journal of Infectious Diseases |volume=155 |issue=3 |pages=445–455 |date=March 1987 |pmid=3805772 |doi=10.1093/infdis/155.3.445}}

In cases in which death occurs, this typically occurs within 14 days of onset. About 1% of all Lassa virus infections result in death. Approximately 15%-20% of those who have required hospitalization for Lassa fever die. The risk of death is greater in those who are pregnant. A "Swollen baby syndrome" may occur in newborns, infants and toddlers with pitting edema, abdominal distension and bleeding.

File:Lassa virus.JPG

Lassa virus is a member of the Arenaviridae, a family of negative-sense, single-stranded RNA viruses.{{Cite journal|last1=Peterson|first1=A. Townsend|last2=Moses|first2=Lina M.|last3=Bausch|first3=Daniel G.|date=2014-08-08|title=Mapping Transmission Risk of Lassa Fever in West Africa: The Importance of Quality Control, Sampling Bias, and Error Weighting|journal=PLOS ONE|volume=9|issue=8|pages=e100711|doi=10.1371/journal.pone.0100711|pmid=25105746|issn=1932-6203|pmc=4126660|bibcode=2014PLoSO...9j0711P|doi-access=free}} Specifically it is an old world arenavirus, which is enveloped, single-stranded, and bi-segmented RNA. Lassa virus contains both a large and a small genome section, with seven lineages identified to date: Lineages I, II, and III from Nigeria;{{Cite journal |last1=Bowen |first1=M. D. |last2=Rollin |first2=P. E. |last3=Ksiazek |first3=T. G. |last4=Hustad |first4=H. L. |last5=Bausch |first5=D. G. |last6=Demby |first6=A. H. |last7=Bajani |first7=M. D. |last8=Peters |first8=C. J. |last9=Nichol |first9=S. T. |date=August 2000 |title=Genetic diversity among Lassa virus strains |journal=Journal of Virology |volume=74 |issue=15 |pages=6992–7004 |doi=10.1128/jvi.74.15.6992-7004.2000 |issn=0022-538X |pmc=112216 |pmid=10888638}} Lineage IV from Sierra Leone, Guinea, and Liberia;{{Cite journal |last1=Wiley |first1=Michael R. |last2=Fakoli |first2=Lawrence |last3=Letizia |first3=Andrew G. |last4=Welch |first4=Stephen R. |last5=Ladner |first5=Jason T. |last6=Prieto |first6=Karla |last7=Reyes |first7=Daniel |last8=Espy |first8=Nicole |last9=Chitty |first9=Joseph A. |last10=Pratt |first10=Catherine B. |last11=Di Paola |first11=Nicholas |last12=Taweh |first12=Fahn |last13=Williams |first13=Desmond |last14=Saindon |first14=Jon |last15=Davis |first15=William G. |date=December 2019 |title=Lassa virus circulating in Liberia: a retrospective genomic characterisation |journal=The Lancet. Infectious Diseases |volume=19 |issue=12 |pages=1371–1378 |doi=10.1016/S1473-3099(19)30486-4 |issn=1474-4457 |pmid=31588039|doi-access=free }} Lineage V from Cote D’Ivoire and Mali Lineage VI from Togo;{{Cite journal |last1=Whitmer |first1=Shannon L. M. |last2=Strecker |first2=Thomas |last3=Cadar |first3=Daniel |last4=Dienes |first4=Hans-Peter |last5=Faber |first5=Kelly |last6=Patel |first6=Ketan |last7=Brown |first7=Shelley M. |last8=Davis |first8=William G. |last9=Klena |first9=John D. |last10=Rollin |first10=Pierre E. |last11=Schmidt-Chanasit |first11=Jonas |last12=Fichet-Calvet |first12=Elisabeth |last13=Noack |first13=Bernd |last14=Emmerich |first14=Petra |last15=Rieger |first15=Toni |date=March 2018 |title=New Lineage of Lassa Virus, Togo, 2016 |journal=Emerging Infectious Diseases |volume=24 |issue=3 |pages=599–602 |doi=10.3201/eid2403.171905 |issn=1080-6059 |pmc=5823357 |pmid=29460758}} and Lineage VII from Benin.{{Cite journal |last1=Mateo |first1=Mathieu |last2=Hortion |first2=Jimmy |last3=Perthame |first3=Emeline |last4=Picard |first4=Caroline |last5=Reynard |first5=Stéphanie |last6=Journeaux |first6=Alexandra |last7=Germain |first7=Clara |last8=Carnec |first8=Xavier |last9=Baillet |first9=Nicolas |last10=Borges-Cardoso |first10=Virginie |last11=Pietrosemoli |first11=Natalia |last12=Vallve |first12=Audrey |last13=Barron |first13=Stéphane |last14=Jourjon |first14=Ophélie |last15=Lacroix |first15=Orianne |date=December 2022 |title=Pathogenesis of recent Lassa virus isolates from lineages II and VII in cynomolgus monkeys |journal=Virulence |volume=13 |issue=1 |pages=654–669 |doi=10.1080/21505594.2022.2060170 |issn=2150-5608 |pmc=9037461 |pmid=35437094}}

File:Mastomys natalensis.jpg

Lassa virus commonly spreads to humans from other animals, specifically the Natal multimammate mouse or African rat, also called the Natal multimammate rat (Mastomys natalensis).{{Cite journal|last1=Richmond|first1=J. K.|last2=Baglole|first2=D. J.|title=Lassa fever: Epidemiology, clinical features, and social consequences|doi=10.1136/bmj.327.7426.1271|journal=BMJ|volume=327|issue=7426|pages=1271–1275|year=2003|pmid=14644972|pmc=286250}} This is probably the most common mouse in equatorial Africa, common in human households and eaten as a delicacy in some areas.{{cite book|editor-last=Werner|editor-first=Dietrich|title=Biological Resources and Migration|publisher=Springer|year=2004|page=363|isbn=978-3-540-21470-0|url=https://archive.org/details/biologicalresour0000unse/page/363}}

The multimammate mouse can quickly produce a large number of offspring, tends to colonize human settlements, increasing the risk of rodent-human contact, and is found throughout the west, central and eastern parts of the African continent.{{cite journal|last1=Goeijenbier|first1=Marco|last2=Wagenaar|first2=Jiri|last3=Goris|first3=Marga|last4=Martina|first4=Byron|last5=Henttonen|first5=Heikki|last6=Vaheri|first6=Antti|last7=Reusken|first7=Chantal|last8=Hartskeerl|first8=Rudy|last9=Osterhaus|first9=Albert|last10=Van Gorp|first10=Eric|title=Rodent-borne hemorrhagic fevers: under-recognized, widely spread and preventable – epidemiology, diagnostics and treatment|journal=Critical Reviews in Microbiology|date=7 June 2012|volume=39|issue=1|pages=26–42|doi=10.3109/1040841X.2012.686481|pmid=22670688|s2cid=31217913|url=}}

Once the mouse has become a carrier, it will excrete the virus throughout the rest of its lifetime through feces and urine creating ample opportunity for exposure. The virus is probably transmitted by contact with the feces or urine of animals accessing grain stores in residences. No study has proven presence in breast milk, but the high level of viremia suggests it may be possible.

Individuals who are at a higher risk of contracting the infection are those who live in rural areas where Mastomys are discovered, and where sanitation is not prevalent. Infection typically occurs by direct or indirect exposure to animal excrement through the respiratory or gastrointestinal tracts. Inhalation of tiny particles of infectious material (aerosol) is believed to be the most significant means of exposure. It is possible to acquire the infection through broken skin or mucous membranes that are directly exposed to infectious material. Transmission from person to person has been established, presenting a disease risk for healthcare workers. The virus is present in urine for between three and nine weeks after infection, and it can be transmitted in semen for up to three months after becoming infected.{{cite web|publisher=Public Health England|url=https://www.gov.uk/guidance/lassa-fever-origins-reservoirs-transmission-and-guidelines|title=Lassa fever: origins, reservoirs, transmission and guidelines|archive-url=https://web.archive.org/web/20160202152827/https://www.gov.uk/guidance/lassa-fever-origins-reservoirs-transmission-and-guidelines|archive-date=2 February 2016|date=5 September 2014|access-date=1 April 2016}}{{cite web|url=https://www.who.int/mediacentre/factsheets/fs179/en/|title=Lassa fever|work=Media Centre Fact Sheet No 179|publisher=World Health Organization|access-date=26 May 2015|url-status=live|archive-url=https://web.archive.org/web/20150605052251/http://www.who.int/mediacentre/factsheets/fs179/en/|archive-date=5 June 2015}}

Image:454277-Q-GYI14-255(1).jpg preparing to test Lassa fever samples.]]

A range of laboratory investigations are performed, where possible, to diagnose the disease and assess its course and complications. The confidence of a diagnosis can be compromised if laboratory tests are not available. One comprising factor is the number of febrile illnesses present in Africa, such as malaria or typhoid fever that could potentially exhibit similar symptoms, particularly for non-specific manifestations of Lassa fever. In cases with abdominal pain, in countries where Lassa is common, Lassa fever is often misdiagnosed as appendicitis and intussusception which delays treatment with the antiviral ribavirin.{{cite journal|last1=Dongo|first1=A. E.|last2=Kesieme|first2=E. B.|last3=Iyamu|first3=C. E.|last4=Okokhere|first4=P. O.|last5=Akhuemokhan|first5=O. C.|last6=Akpede|first6=G. O.|year=2013|title=Lassa fever presenting as acute abdomen: a case series|journal=Virology Journal|volume=10|pages=124|doi=10.1186/1743-422X-10-123|pmid=23597024|pmc=3639802 |doi-access=free }} In West Africa, where Lassa is most common, it is difficult to diagnose due to the absence of proper equipment to perform testing.{{Cite journal | last1 = Asogun | first1 = D. A. | last2 = Adomeh | first2 = D. I. | last3 = Ehimuan | first3 = J. | last4 = Odia | first4 = I. | last5 = Hass | first5 = M. | last6 = Gabriel | first6 = M. | last7 = Olschläger | first7 = S. | last8 = Becker-Ziaja | first8 = B. | last9 = Folarin | first9 = O. | last10 = Phelan | first10 = E. | last11 = Ehiane | first11 = P. E. | last12 = Ifeh | first12 = V. E. | last13 = Uyigue | first13 = E. A. | last14 = Oladapo | first14 = Y. T. | last15 = Muoebonam | first15 = E. B. | last16 = Osunde | first16 = O. | last17 = Dongo | first17 = A. | last18 = Okokhere | first18 = P. O. | last19 = Okogbenin | first19 = S. A. | last20 = Momoh | first20 = M. | last21 = Alikah | first21 = S. O. | last22 = Akhuemokhan | first22 = O. C. | last23 = Imomeh | first23 = P. | last24 = Odike | first24 = M. A. | last25 = Gire | first25 = S. | last26 = Andersen | first26 = K. | last27 = Sabeti | first27 = P. C. | last28 = Happi | first28 = C. T. | last29 = Akpede | first29 = G. O. | last30 = Günther | first30 = S. | editor1-last = Bausch | editor1-first = Daniel G | title = Molecular Diagnostics for Lassa Fever at Irrua Specialist Teaching Hospital, Nigeria: Lessons Learnt from Two Years of Laboratory Operation | doi = 10.1371/journal.pntd.0001839 | journal = PLOS Neglected Tropical Diseases | volume = 6 | issue = 9 | pages = e1839 | year = 2012 | pmid = 23029594 | pmc =3459880 | doi-access = free }}

The United States FDA has yet to approve a widely validated laboratory test for Lassa, but there are tests that have been able to provide definitive proof of the presence of the LASV virus. These tests include cell cultures, PCR, ELISA antigen assays, plaque neutralization assays, and immunofluorescence essays. However, immunofluorescence essays provide less definitive proof of Lassa infection. An ELISA test for antigen and Immunoglobulin M antibodies give 88% sensitivity and 90% specificity for the presence of the infection. Other laboratory findings in Lassa fever include lymphocytopenia (low lymphocyte white blood cell count), thrombocytopenia (low platelets), and elevated aspartate transaminase levels in the blood. Lassa fever virus can also be found in cerebrospinal fluid.{{Cite journal | last1 = Günther | first1 = S. | last2 = Weisner | first2 = B. | last3 = Roth | first3 = A. | last4 = Grewing | first4 = T. | last5 = Asper | first5 = M. | last6 = Drosten | first6 = C. |author-link6=Christian Drosten | last7 = Emmerich | first7 = P. | last8 = Petersen | first8 = J. | last9 = Wilczek | first9 = M. | doi = 10.1086/322033 | last10 = Schmitz | first10 = H. | title = Lassa Fever Encephalopathy: Lassa Virus in Cerebrospinal Fluid but Not in Serum | journal = The Journal of Infectious Diseases | volume = 184 | issue = 3 | pages = 345–349 | year = 2001 | pmid = 11443561 | doi-access = free }}

{{Main|Prevention of viral hemorrhagic fever}}

File:LassaRat.png

Control of the Mastomys rodent population is impractical, so measures focus on keeping rodents out of homes and food supplies, encouraging effective personal hygiene, storing grain and other foodstuffs in rodent-proof containers, and disposing of garbage far from the home to help sustain clean households.{{cite journal |vauthors=Ogbu O, Ajuluchukwu E, Uneke CJ |title=Lassa fever in West African sub-region: an overview |journal=J Vector Borne Dis |volume=44 |issue=1 |pages=1–11 |date=March 2007 |pmid=17378212 |doi= |url=}} Gloves, masks, laboratory coats, and goggles are advised while in contact with an infected person, to avoid contact with blood and body fluids.{{cite journal |vauthors=Weber DJ, Rutala WA, Fischer WA, Kanamori H, Sickbert-Bennett EE |title=Emerging infectious diseases: Focus on infection control issues for novel coronaviruses (Severe Acute Respiratory Syndrome-CoV and Middle East Respiratory Syndrome-CoV), hemorrhagic fever viruses (Lassa and Ebola), and highly pathogenic avian influenza viruses, A(H5N1) and A(H7N9) |journal=Am J Infect Control |volume=44 |issue=5 Suppl |pages=e91–e100 |date=May 2016 |pmid=27131142 |pmc=7132650 |doi=10.1016/j.ajic.2015.11.018 |url=}} These issues in many countries are monitored by a department of public health. In less developed countries, these types of organizations may not have the necessary means to effectively control outbreaks.{{Citation |title=Driving and Public Health |date=2021-11-23 |url=http://dx.doi.org/10.1093/obo/9780199756797-0211 |work=Public Health |publisher=Oxford University Press |doi=10.1093/obo/9780199756797-0211 |isbn=978-0-19-975679-7 |access-date=2022-04-23|url-access=subscription }}

There is no vaccine for humans as of 2023.{{cite web |title=Lassa |url=https://vhfc.org/diseases/lassa/ |website=Viral Hemorrhagic Fever Consortium |access-date=18 June 2019 |archive-date=18 June 2019 |archive-url=https://web.archive.org/web/20190618110029/https://vhfc.org/diseases/lassa/ |url-status=live }} Researchers at the United States Army Medical Research Institute of Infectious Diseases facility had a promising vaccine candidate in 2002.{{cite book |author=Preston, Richard |title=The demon in the freezer: a true story |url=https://archive.org/details/demoninfreezertr00pres |url-access=registration |publisher=Random House |location=New York |year=2002 |isbn=978-0-375-50856-1 |author-link=Richard Preston }} They have developed a replication-competent vaccine against Lassa virus based on recombinant vesicular stomatitis virus vectors expressing the Lassa virus glycoprotein. After a single intramuscular injection, test primates have survived lethal challenge, while showing no clinical symptoms.{{cite journal |author=Geisbert TW |title=Development of a New Vaccine for the Prevention of Lassa Fever |journal=PLOS Med. |volume=2 |issue=6 |pages=e183 |year=2005 |pmid=15971954 |doi=10.1371/journal.pmed.0020183 |pmc=1160587 |author2=Jones S |author3=Fritz EA |last4=Shurtleff |first4=Amy C. |last5=Geisbert |first5=Joan B. |last6=Liebscher |first6=Ryan |last7=Grolla |first7=Allen |last8=Ströher |first8=Ute |last9=Fernando |first9=Lisa |doi-access=free }}

Treatment is directed at addressing dehydration and improving symptoms.

The antiviral medication ribavirin has been recommended,{{Cite journal |last1=Salam |first1=Alex P. |last2=Duvignaud |first2=Alexandre |last3=Jaspard |first3=Marie |last4=Malvy |first4=Denis |last5=Carroll |first5=Miles |last6=Tarning |first6=Joel |last7=Olliaro |first7=Piero L. |last8=Horby |first8=Peter W. |date=2022-03-30 |title=Ribavirin for treating Lassa fever: A systematic review of pre-clinical studies and implications for human dosing |journal=PLOS Neglected Tropical Diseases |language=en |volume=16 |issue=3 |pages=e0010289 |doi=10.1371/journal.pntd.0010289 |issn=1935-2735 |pmc=9000057 |pmid=35353804 |doi-access=free }} but evidence to support its use is weak. Some evidence has found that it may worsen outcomes in certain cases. Fluid replacement, blood transfusions, and medication for low blood pressure may be required. Intravenous interferon therapy has also been used.{{Cite journal |last1=Adewuyi |first1=G. M. |last2=Fowotade |first2=A. |last3=Adewuyi |first3=B. T. |date=2009 |title=Lassa Fever: Another Infectious Menace |url=https://www.ajol.info/index.php/ajcem/article/view/43407 |journal=African Journal of Clinical and Experimental Microbiology |language=en |volume=10 |issue=3 |doi=10.4314/ajcem.v10i3.43407 |issn=1595-689X |doi-access=free |access-date=28 April 2023 |archive-date=28 April 2023 |archive-url=https://web.archive.org/web/20230428060934/https://www.ajol.info/index.php/ajcem/article/view/43407 |url-status=live }}{{Cite journal |last1=Baize |first1=Sylvain |last2=Pannetier |first2=Delphine |last3=Faure |first3=Caroline |last4=Marianneau |first4=Philippe |last5=Marendat |first5=Ingrid |last6=Georges-Courbot |first6=Marie-Claude |last7=Deubel |first7=Vincent |date=2006-04-01 |title=Role of interferons in the control of Lassa virus replication in human dendritic cells and macrophages |journal=Microbes and Infection |language=en |volume=8 |issue=5 |pages=1194–1202 |doi=10.1016/j.micinf.2006.02.002 |pmid=16621649 |issn=1286-4579|doi-access=free }}

A potential novel treatment, the NMT inhibitor, has been shown to completely inhibit lassa infection in cells based assays by targeting Z protein and SSP for degradation.{{Cite journal |last1=Witwit |first1=Haydar |last2=Betancourt |first2=Carlos Alberto |last3=Cubitt |first3=Beatrice |last4=Khafaji |first4=Roaa |last5=Kowalski |first5=Heinrich |last6=Jackson |first6=Nathaniel |last7=Ye |first7=Chengjin |last8=Martinez-Sobrido |first8=Luis |last9=de la Torre |first9=Juan C. |date=2024-08-26 |title=Cellular N-Myristoyl Transferases Are Required for Mammarenavirus Multiplication |journal=Viruses |language=en |volume=16 |issue=9 |pages=1362 |doi=10.3390/v16091362 |doi-access=free |pmid=39339839 |pmc=11436053 |issn=1999-4915}} Favipiravir, a nucleoside analogue, has been shown to be effective at treating Lassa fever in immunocompetent mouse, guinea pigs and macaques.{{cite journal |last1=Oestereich |first1=L |last2=Rieger |first2=T |last3=Lüdtke |first3=A |last4=Ruibal |first4=P |last5=Wurr |first5=S |last6=Pallasch |first6=E |last7=Bockholt |first7=S |last8=Krasemann |first8=S |last9=Muñoz-Fontela |first9=C |last10=Günther |first10=S |title=Efficacy of Favipiravir Alone and in Combination With Ribavirin in a Lethal, Immunocompetent Mouse Model of Lassa Fever. |journal=The Journal of Infectious Diseases |date=15 March 2016 |volume=213 |issue=6 |pages=934–8 |doi=10.1093/infdis/jiv522 |pmid=26531247 |pmc=4760419}}{{cite journal |last1=Safronetz |first1=David |last2=Rosenke |first2=Kyle |last3=Westover |first3=Jonna B. |last4=Martellaro |first4=Cynthia |last5=Okumura |first5=Atsushi |last6=Furuta |first6=Yousuke |last7=Geisbert |first7=Joan |last8=Saturday |first8=Greg |last9=Komeno |first9=Takashi |last10=Geisbert |first10=Thomas W. |last11=Feldmann |first11=Heinz |last12=Gowen |first12=Brian B. |title=The broad-spectrum antiviral favipiravir protects guinea pigs from lethal Lassa virus infection post-disease onset |journal=Scientific Reports |date=12 October 2015 |volume=5 |issue=1 |page=14775 |doi=10.1038/srep14775 |pmid=26456301 |pmc=4600983|bibcode=2015NatSR...514775S }}{{cite journal |last1=Rosenke |first1=K |last2=Feldmann |first2=H |last3=Westover |first3=JB |last4=Hanley |first4=PW |last5=Martellaro |first5=C |last6=Feldmann |first6=F |last7=Saturday |first7=G |last8=Lovaglio |first8=J |last9=Scott |first9=DP |last10=Furuta |first10=Y |last11=Komeno |first11=T |last12=Gowen |first12=BB |last13=Safronetz |first13=D |title=Use of Favipiravir to Treat Lassa Virus Infection in Macaques. |journal=Emerging Infectious Diseases |date=September 2018 |volume=24 |issue=9 |pages=1696–1699 |doi=10.3201/eid2409.180233 |pmid=29882740 |pmc=6106425}} A case report showed combination favipiravir with ribavirin is effective for lassa fever, with two patients survived.{{cite journal |last1=Raabe |first1=Vanessa N |last2=Kann |first2=Gerrit |last3=Ribner |first3=Bruce S |last4=Morales |first4=Andres |last5=Varkey |first5=Jay B |last6=Mehta |first6=Aneesh K |last7=Lyon |first7=G Marshall |last8=Vanairsdale |first8=Sharon |title=Favipiravir and Ribavirin Treatment of Epidemiologically Linked Cases of Lassa Fever |journal=Clinical Infectious Diseases |date=1 September 2017 |volume=65 |issue=5 |pages=855–859 |doi=10.1093/cid/cix406 |pmid=29017278 |pmc=5682919}} In vivo, the EC₅₀ of favipiravir is 2.89 μg.mL⁻¹and doses larger than 1200 mg twice a day should have the capability to strongly reduce the production infectious virus.{{cite journal |last1=Lingas |first1=Guillaume |last2=Rosenke |first2=Kyle |last3=Safronetz |first3=David |last4=Guedj |first4=Jérémie |title=Lassa viral dynamics in non-human primates treated with favipiravir or ribavirin |journal=PLOS Computational Biology |date=7 January 2021 |volume=17 |issue=1 |pages=e1008535 |doi=10.1371/journal.pcbi.1008535 |doi-access=free |pmid=33411731 |pmc=7817048|bibcode=2021PLSCB..17E8535L }}

When Lassa fever infects pregnant women late in their third trimester, inducing delivery is necessary for the mother to have a good chance of survival.{{cite journal |vauthors=Price ME, Fisher-Hoch SP, Craven RB, McCormick JB |title=A prospective study of maternal and fetal outcome in acute Lassa fever infection during pregnancy |journal=BMJ |volume=297 |issue=6648 |pages=584–7 |date=September 1988 |pmid=3139220 |pmc=1834487 |doi=10.1136/bmj.297.6648.584 }} This is because the virus has an affinity for the placenta and other highly vascular tissues. The fetus has only a one in ten chance of survival no matter what course of action is taken; hence, the focus is always on saving the life of the mother.{{cite web|last1=Samuel|first1=Daso|title=Lassa fever... What you need to know.|url=http://www.aaua.edu.ng/a/health_centre/files/Lassa_fever_97.pdf|access-date=1 February 2017|url-status=live|archive-url=https://web.archive.org/web/20170625074524/http://www.aaua.edu.ng/a/health_centre/files/Lassa_fever_97.pdf|archive-date=25 June 2017}}{{Cite journal |last=OKOGBENIN |first=SYLVANUS |title=CLINICAL FEATURES AND MANAGEMENT OF LASSA FEVER. |url=https://cdn.who.int/media/docs/default-source/blue-print/day1_session1_1_sylvanus-okogbenin_lassa-vaccine-meeting_nigeria.pdf?sfvrsn=14a26bbf_3 |journal=World Health Organization |pages=34 |access-date=13 March 2024 |archive-date=13 March 2024 |archive-url=https://web.archive.org/web/20240313044553/https://cdn.who.int/media/docs/default-source/blue-print/day1_session1_1_sylvanus-okogbenin_lassa-vaccine-meeting_nigeria.pdf?sfvrsn=14a26bbf_3 |url-status=live }}

About 15–20% of hospitalized people with Lassa fever will die from the illness. The overall case fatality rate is estimated to be 1%, but during epidemics, mortality can climb as high as 50%. The mortality rate is greater than 80% when it occurs in pregnant women during their third trimester; fetal death also occurs in nearly all those cases. Abortion decreases the risk of death to the mother.Centers for Disease Control and Prevention, [https://www.cdc.gov/vhf/lassa/symptoms/index.html "Lassa Fever, Signs and Symptoms"] {{webarchive|url=https://web.archive.org/web/20170709214337/https://www.cdc.gov/vhf/lassa/symptoms/index.html |date=9 July 2017 }} Some survivors experience lasting effects of the disease,{{Cite journal | doi = 10.1136/bmj.285.6347.1001 | last1 = Emond | first1 = R. T. | last2 = Bannister | first2 = B. | last3 = Lloyd | first3 = G. | last4 = Southee | first4 = T. J. | last5 = Bowen | first5 = E. T. | title = A case of Lassa fever: Clinical and virological findings | journal = British Medical Journal (Clinical Research Ed.) | volume = 285 | issue = 6347 | pages = 1001–1002 | year = 1982 | pmid = 6812716 | pmc = 1500383}} and can include partial or complete deafness.

Because of treatment with ribavirin, fatality rates have declined.{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs179/en/|title=Lassa fever|website=World Health Organization|language=en-GB|access-date=2017-09-11|archive-date=1 November 2016|archive-url=https://web.archive.org/web/20161101083748/http://www.who.int/mediacentre/factsheets/fs179/en/|url-status=live}}{{Cite journal|last1=McCormick|first1=J. B.|last2=King|first2=I. J.|last3=Webb|first3=P. A.|last4=Scribner|first4=C. L.|last5=Craven|first5=R. B.|last6=Johnson|first6=K. M.|last7=Elliott|first7=L. H.|last8=Belmont-Williams|first8=R.|date=1986-01-02|title=Lassa fever. Effective therapy with ribavirin|journal=The New England Journal of Medicine|volume=314|issue=1|pages=20–26|doi=10.1056/NEJM198601023140104|issn=0028-4793|pmid=3940312}}

file:Lassa fever Outbreak Distribution Map.svg

There are about 300,000 to 500,000 cases which result in 5,000 deaths a year. One estimate places {{Cite web |title=Lassa Fever |url=https://africacdc.org/disease/lassa-fever/ |access-date=2022-04-23 |website=Africa CDC |language=en-GB |archive-date=29 June 2022 |archive-url=https://web.archive.org/web/20220629132022/https://africacdc.org/disease/lassa-fever/ |url-status=live }} the number as high as 3 million cases per year.

Estimates of Lassa fever are complicated by the lack of easy-available diagnosis, limited public health surveillance infrastructure, and high clustering of incidence near high intensity sampling.

The infection affects females 1.2 times more than males. The age group predominantly infected is 21–30 years.{{Cite web|url=https://www.premiumtimesng.com/news/headlines/381433-lassa-fever-nigerias-death-toll-reaches-144.html|title=Lassa Fever: Nigeria's death toll reaches 144|last=Owoseye|first=Ayodamola|date=2020-03-11|language=en-GB|access-date=2020-03-13|archive-date=12 March 2020|archive-url=https://web.archive.org/web/20200312154450/https://www.premiumtimesng.com/news/headlines/381433-lassa-fever-nigerias-death-toll-reaches-144.html|url-status=live}}

Lassa high risk areas are near the western and eastern extremes of West Africa. As of 2018, the Lassa belt includes Guinea, Nigeria, Sierra Leone and Liberia.{{cite journal|author1=David Greenky|author2=Barbara Knust|author3=Eric J. Dziuban|title=What Pediatricians Should Know About Lassa Virus|journal=JAMA Pediatrics|year=2018|volume=172|issue=5|pages=407–408|doi=10.1001/jamapediatrics.2017.5223|pmid=29507948|pmc=5970952}} As of 2003, 10-16% of people in Sierra Leone and Liberia admitted to hospital had the virus. The case fatality rate for those who are hospitalized for the disease is about 15-20%. Research showed a twofold increase risk of infection for those living in close proximity to someone with infection symptoms within the last year.{{Cite web |title=Lassa fever |url=https://www.who.int/news-room/fact-sheets/detail/lassa-fever#:~:text=The%20overall%20case%20fatality%20rate,treatment%20improves%20chances%20of%20survival. |access-date=2025-03-09 |website=www.who.int |language=en}}

The high risk areas cannot be well defined by any known biogeographical or environmental breaks except for the multimammate rat, particularly Guinea (Kindia, Faranah and Nzérékoré regions), Liberia (mostly in Lofa, Bong, and Nimba counties), Nigeria (in about 10 of 36 states) and Sierra Leone (typically from Kenema and Kailahun districts). It is less common in the Central African Republic, Mali, Senegal and other nearby countries, and less common yet in Ghana and the Democratic Republic of the Congo. Benin had its first confirmed cases in 2014, and Togo had its first confirmed cases in 2016.

As of 2013, the spread of Lassa outside of West Africa had been very limited. Twenty to thirty cases had been described in Europe, as being caused by importation through infected individuals. These cases found outside of West Africa were found to have a high fatality risk because of the delay of diagnosis and treatment due to being unaware of the risk associated with the symptoms. Imported cases have not manifested in larger epidemics outside of Africa due to a lack of human to human transmission in hospital settings. An exception had occurred in 2003 when a healthcare worker became infected before the person showed clear symptoms.

In October 2024, a resident of Iowa, United States has passed away due to Lassa fever following a trip to West Africa, as reported by the Iowa Department of Health and Human Services.{{Cite web |last=Branswell |first=Helen |date=2024-10-28 |title=U.S. death from Lassa fever, an Ebola-like virus, is reported in Iowa |url=https://www.statnews.com/2024/10/28/lassa-fever-us-case-iowa-death/ |access-date=2024-10-29 |website=STAT |language=en-US}} Health officials indicate the person likely contracted Lassa fever—transmissible through contact with infected body fluids or, potentially, with rodents while abroad, according to guidance from the Centers for Disease Control and Prevention.{{Cite web |last=CDC |date=2024-10-28 |title=Lassa Fever Suspected in Death of U.S. Traveler Returning from West Africa |url=https://www.cdc.gov/media/releases/2024/s1028-lassa-fever.html |access-date=2024-10-29 |website=CDC Newsroom |language=en-us}}

An outbreak of Lassa fever occurred in Nigeria during 2018 and spread to 18 of the country's states; it was the largest outbreak of Lassa recorded.{{cite journal|last1=Maxmen|first1=Amy|title=Deadly Lassa-fever outbreak tests Nigeria's revamped health agency|journal=Nature|volume=555|issue=7697|pages=421–422|date=15 March 2018|doi=10.1038/d41586-018-03171-y|pmid=29565399|language=EN|bibcode=2018Natur.555..421M|doi-access=free}}{{cite news|title=On the frontlines of the fight against Lassa fever in Nigeria|url=https://www.who.int/features/2018/lassa-fever-nigeria/en/|archive-url=https://web.archive.org/web/20180318094709/http://www.who.int/features/2018/lassa-fever-nigeria/en/|url-status=dead|archive-date=18 March 2018|work=World Health Organization|date=March 2018}}{{cite news|last1=Beaubien|first1=Jason|title=Nigeria Faces Mystifying Spike in Deadly Lassa Fever|url=https://www.npr.org/sections/goatsandsoda/2018/03/19/587603462/nigeria-faces-mystiifying-spike-in-deadly-lassa-fever|work=NPR|date=19 March 2018|language=en|access-date=18 June 2019|archive-date=19 March 2018|archive-url=https://web.archive.org/web/20180319235226/https://www.npr.org/sections/goatsandsoda/2018/03/19/587603462/nigeria-faces-mystiifying-spike-in-deadly-lassa-fever|url-status=live}} The outbreak primarily affected Nigeria, Liberia, Sierra Leone, and Guinea, with cases reported since January 2018.{{Cite journal |last1=Balogun |first1=Oluwafemi O. |last2=Akande |first2=Oluwatosin W. |last3=Hamer |first3=Davidson H. |date=2020-11-23 |title=Lassa Fever: An Evolving Emergency in West Africa |journal=The American Journal of Tropical Medicine and Hygiene |volume=104 |issue=2 |pages=466–473 |doi=10.4269/ajtmh.20-0487 |issn=1476-1645 |pmc=7866331 |pmid=33236712}}{{Cite web |title=Lassa Fever – Nigeria |url=https://www.who.int/emergencies/disease-outbreak-news/item/01-march-2018-lassa-fever-nigeria-en |access-date=2025-03-21 |website=www.who.int |language=en}}

As of 25 February 2018, there were 1081 suspected cases and 90 reported deaths; 317 of the cases and 72 deaths were confirmed as Lassa which increased to a total of 431 reported cases in 2018.{{cite news|url=https://www.who.int/csr/don/01-march-2018-lassa-fever-nigeria/en/|archive-url=https://web.archive.org/web/20180301141952/http://www.who.int/csr/don/01-march-2018-lassa-fever-nigeria/en/|url-status=dead|archive-date=1 March 2018|title=Lassa Fever – Nigeria|date=1 March 2018|work=World Health Organization}} During the outbreak, a total of 3,498 infections were recorded, resulting in 171 deaths. Nigeria was the most severely impacted, accounting for over half of the total cases and fatalities. The World Health Organization (WHO) reported on 27 March 2018 that 1,081 suspected cases and 90 deaths had occurred.{{Cite web |date=2025-03-20 |title=Lassa Fever {{!}} WHO {{!}} Regional Office for Africa |url=https://www.afro.who.int/health-topics/lassa-fever |access-date=2025-03-21 |website=www.afro.who.int |language=en}} It was one of the most severe Lassa fever outbreaks in the region in recent years, exhausting a significant portion of the global emergency medical response resources.{{Cite web |last=CDC |date=2025-01-31 |title=About Lassa Fever |url=https://www.cdc.gov/lassa-fever/about/index.html |access-date=2025-03-21 |website=Lassa Fever |language=en-us}}

Health organizations, including Doctors Without Borders and the WHO, collaborated with national governments to contain the outbreak through mass awareness campaigns, improved surveillance, and emergency medical interventions. In total, 2.1 million people received preventive health education, while emergency treatment centers were established across affected regions.{{Cite web |title=Meeting of the Lassa Fever Coalition Governing Entity (LGE) {{!}} West African Health Organization |url=https://www.wahooas.org/web-ooas/en/actualites/meeting-lassa-fever-coalition-governing-entity-lge |access-date=2025-03-21 |website=www.wahooas.org}}{{Cite journal |last1=Aloke |first1=Chinyere |last2=Obasi |first2=Nwogo Ajuka |last3=Aja |first3=Patrick Maduabuchi |last4=Emelike |first4=Chinedum Uche |last5=Egwu |first5=Chinedu Ogbonnia |last6=Jeje |first6=Olamide |last7=Edeogu |first7=Chuks Oswald |last8=Onisuru |first8=Olalekan Olugbenga |last9=Orji |first9=Obasi Uche |last10=Achilonu |first10=Ikechukwu |date=2023-01-03 |title=Combating Lassa Fever in West African Sub-Region: Progress, Challenges, and Future Perspectives |journal=Viruses |volume=15 |issue=1 |pages=146 |doi=10.3390/v15010146 |doi-access=free |issn=1999-4915 |pmc=9864412 |pmid=36680186}}

Nigeria was the hardest hit country, with 2,121 cases and 132 deaths reported. The outbreak affected 18 of its 36 states, with the highest cases recorded in Edo, Ondo, and Ebonyi States. The Nigerian Ministry of Health launched an extensive awareness campaign and deployed medical teams to affected areas. Emergency supplies, including ribavirin (an antiviral drug), were distributed, and treatment centers were set up in federal hospitals to manage severe cases.{{Cite web |title=Nigeria: spread of Lassa fever, by status 2023 {{!}} Statista |url=https://www.statista.com/statistics/1126777/number-of-lassa-fever-cases-in-nigeria/#:~:text=From%20January%20to%20October%202023,in%20several%20West%20African%20countries. |archive-url=http://web.archive.org/web/20240807221000/https://www.statista.com/statistics/1126777/number-of-lassa-fever-cases-in-nigeria/ |archive-date=2024-08-07 |access-date=2025-03-21 |website=Statista |language=en}}{{Cite web |title=Lassa Fever - Nigeria |url=https://www.who.int/emergencies/disease-outbreak-news/item/lassa-fever---nigeria |access-date=2025-03-21 |website=www.who.int |language=en}}

{{Infobox News event

| image = File:2009 Africa epidemic.png

| caption = Countries affected by the epidemic

| map_size = 50

| place = Sierra Leone, Liberia, Guinea, and Nigeria

| casualties1 = 1,100 dead

| casualties2 = 25,000 suspected cases

| casualties3 =

| notes =

}}

The total cases in Nigeria in 2019 was 810 with 167 deaths, the largest case fatality rate (23.3%) until then.{{Cite web|url=https://qz.com/africa/1814567/coronavirus-less-deadly-than-nigeria-lassa-fever-viral-outbreak/|title=Nigeria is already dealing with a deadlier viral outbreak than the coronavirus epidemic|last=Edward-Ekpu|first=Uwagbale|website=Quartz Africa|date=8 March 2020|language=en|access-date=2020-03-13|archive-date=13 March 2020|archive-url=https://web.archive.org/web/20200313035110/https://qz.com/africa/1814567/coronavirus-less-deadly-than-nigeria-lassa-fever-viral-outbreak/|url-status=live}}

The epidemic started from the second week of the January. By the tenth week the total number of cases has risen to 855 and deaths to 144, the case fatality rate of 16.8%.{{Cite web|url=https://www.ncdc.gov.ng/themes/common/files/sitreps/f9c5b3d7327f20c15c3916ff5514fb14.pdf|title=Lassa fever situation report|website=Nigeria Centre for Disease Control|date=March 2020|access-date=13 March 2020|archive-date=9 April 2020|archive-url=https://web.archive.org/web/20200409140325/https://www.ncdc.gov.ng/themes/common/files/sitreps/f9c5b3d7327f20c15c3916ff5514fb14.pdf|url-status=dead}}

On the 8th of December 2021, the Nigeria Centre for Disease Control (NCDC) was notified of the death of two persons from Lassa fever.{{Cite web |title=Nigeria Centre for Disease Control |url=https://ncdc.gov.ng/news/349/ncdc-intensifies-activities-for-lassa-fever-surveillance-and-response-following-outbreaks-of-cases-in-nigeria |access-date=2022-04-23 |website=ncdc.gov.ng |archive-date=15 April 2022 |archive-url=https://web.archive.org/web/20220415013226/https://www.ncdc.gov.ng/news/349/ncdc-intensifies-activities-for-lassa-fever-surveillance-and-response-following-outbreaks-of-cases-in-nigeria |url-status=live }}

The epidemic took a new form, from 3 to 30 January 2022, 211 laboratory confirmed Lassa fever cases including 40 deaths (case fatality ratio: 19%) have been cumulatively reported in 14 of the 36 Nigerian states and the Federal Capital Territory across the country.{{Cite web |title=Lassa Fever - Nigeria |url=https://www.who.int/emergencies/disease-outbreak-news/item/lassa-fever---nigeria |access-date=2022-04-23 |website=www.who.int |language=en |archive-date=16 February 2022 |archive-url=https://web.archive.org/web/20220216001642/https://www.who.int/emergencies/disease-outbreak-news/item/lassa-fever---nigeria |url-status=live }} In total from January until March, 132 deaths have been reported with a case fatality rate (CFR) of 19.1% which is lower than the CFR for the same period in 2021 (21.0%).{{Cite web |title=NCDC Lassa fever Situation Report Epi Week 13: 28 March - 3 April, 2022 - Nigeria |url=https://reliefweb.int/report/nigeria/ncdc-lassa-fever-situation-report-epi-week-13-28-march-3-april-2022 |access-date=2022-04-23 |website=ReliefWeb |date=17 April 2022 |language=en |archive-date=23 April 2022 |archive-url=https://web.archive.org/web/20220423082720/https://reliefweb.int/report/nigeria/ncdc-lassa-fever-situation-report-epi-week-13-28-march-3-april-2022 |url-status=live }}

In October 2024, a resident of Iowa, United States, died from Lassa fever after traveling to West Africa. This case, confirmed by the Iowa Department of Health and Human Services, underscores the risk of international spread. The individual likely contracted the virus abroad, as Lassa fever spreads through infected rodent excreta or bodily fluids. Health authorities are monitoring close contacts to prevent further transmission.{{Cite web |last=CDC |date=2024-10-28 |title=Lassa Fever Suspected in Death of U.S. Traveler Returning from West Africa |url=https://www.cdc.gov/media/releases/2024/s1028-lassa-fever.html |access-date=2024-10-29 |website=CDC Newsroom |language=en-us}}{{Cite web |last=ProLife HC |title=Lassa Fever Death in Iowa After West African Travel |url=https://prolifehc.com/post/Lassa-Fever-Death-in-Iowa-After-West-African-Travel |date=2024-10-29 |access-date=2024-10-29}}

Nigeria is grappling with a severe Lassa fever outbreak, reporting 535 confirmed cases and 98 deaths across 14 states since January, with a case fatality rate of 18.3%.{{Cite web |last=Anyaogu |first=Isaac |date=March 11, 2025 |title=Nigeria steps up fight against Lassa fever outbreak after 98 deaths this year |url=https://www.reuters.com/business/healthcare-pharmaceuticals/nigeria-steps-up-fight-against-lassa-fever-outbreak-after-98-deaths-this-year-2025-03-11/ |access-date=3 April 2025 |website=Reuters}} The disease spread to a patient who travelled to the UK, prompting contact tracing efforts in both countries. The Nigerian Centre for Disease Control (NCDC) issued a renewed advisory urging heightened awareness and preventative measures.

Lassa fever is endemic in Liberia. From 1 January 2017 through 23 January 2018, 91 suspected cases were reported from six counties: Bong, Grand Bassa, Grand Kru, Lofa, Margibi, and Nimba. Thirty-three of these cases were laboratory confirmed, including 15 deaths (case fatality rate for confirmed cases = 45.4%).{{Cite web|url=https://www.who.int/csr/don/22-february-2018-lassa-fever-liberia/en/|archive-url=https://web.archive.org/web/20180222165208/http://www.who.int/csr/don/22-february-2018-lassa-fever-liberia/en/|url-status=dead|archive-date=22 February 2018|title=WHO {{!}} Lassa Fever – Liberia|website=WHO|access-date=2020-03-13}}

Liberia recorded 108 infections and 9 fatalities associated with 2018 Nigeria outbreak. The outbreak was concentrated in Lofa and Nimba Counties, where healthcare infrastructure was already fragile due to past epidemics. The Liberian Ministry of Health, supported by international partners, deployed mobile clinics and trained health workers to improve case detection and management.{{Cite web |title=Lassa Fever – Liberia |url=https://www.who.int/emergencies/disease-outbreak-news/item/22-february-2018-lassa-fever-liberia-en |access-date=2025-03-21 |website=www.who.int |language=en}}

In February 2020, a total of 24 confirmed cases with nine associated deaths has been reported from nine health districts in six counties. Grand Bossa and Bong counties account for 20 of the confirmed cases.{{Cite web|url=http://outbreaknewstoday.com/liberia-reports-increase-in-lassa-fever-45925/|title=Liberia reports increase in Lassa fever|date=2020-02-04|website=Outbreak News Today|language=en-US|access-date=2020-03-13|archive-date=5 March 2020|archive-url=https://web.archive.org/web/20200305061913/http://outbreaknewstoday.com/liberia-reports-increase-in-lassa-fever-45925/|url-status=live}}

Sierra Leone reported 129 infections, with 12 deaths, in 2018. The outbreak was especially severe in Kenema and Bo Districts, where local health authorities struggled with limited resources. Public health officials launched community awareness initiatives to educate citizens about hygiene practices to prevent further spread.{{Cite web |title=Lassa Fever – The Netherlands (ex –Sierra Leone) |url=https://www.who.int/emergencies/disease-outbreak-news/item/2019-DON213 |access-date=2025-03-21 |website=www.who.int |language=en}}

Guinea experienced 98 cases and 8 fatalities, making it one of the least affected countries in the region in 2018. The outbreak was largely contained due to early intervention measures, including stringent border screenings and rapid response teams.{{Cite web |title=Lassa fever - Guinea |url=https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON382 |access-date=2025-03-22 |website=www.who.int |language=en}}{{Cite journal |last1=Keïta |first1=Mory |last2=Kizerbo |first2=Georges Alfred |last3=Subissi |first3=Lorenzo |last4=Traoré |first4=Fodé Amara |last5=Doré |first5=Ahmadou |last6=Camara |first6=Mohamed Fode |last7=Barry |first7=Ahmadou |last8=Pallawo |first8=Raymond |last9=Baldé |first9=Mamadou Oury |last10=Magassouba |first10=Nfaly |last11=Djingarey |first11=Mamoudou Harouna |last12=Fall |first12=Ibrahima Socé |date=2019-07-10 |title=Investigation of a cross-border case of Lassa fever in West Africa |journal=BMC Infectious Diseases |volume=19 |issue=1 |pages=606 |doi=10.1186/s12879-019-4240-8 |doi-access=free |issn=1471-2334 |pmc=6621975 |pmid=31291900}}

The disease was identified in Nigeria in 1969. It is named after the town of Lassa, where it was discovered.

A prominent expert in the disease, Aniru Conteh, died from the disease.{{cite journal |title=Aniru Conteh |journal=BMJ |date=1 May 2004 |volume=328 |issue=7447 |pages=1078.1 |doi=10.1136/bmj.328.7447.1078|pmc=403863 |last1=Mellor |first1=N. }}

The Lassa virus is one of several viruses identified by WHO as a likely cause of a future epidemic. They therefore list it for urgent research and development to develop new diagnostic tests, vaccines, and medicines.{{cite web|last1=Kieny|first1=Marie-Paule|title=After Ebola, a Blueprint Emerges to Jump-Start R&D|url=https://blogs.scientificamerican.com/guest-blog/after-ebola-a-blueprint-emerges-to-jump-start-r-d/|website=Scientific American Blog Network|access-date=13 December 2016|url-status=live|archive-url=https://web.archive.org/web/20161220134725/https://blogs.scientificamerican.com/guest-blog/after-ebola-a-blueprint-emerges-to-jump-start-r-d/|archive-date=20 December 2016}}{{cite web|title=LIST OF PATHOGENS|url=https://www.who.int/csr/research-and-development/list_of_pathogens/en/|website=World Health Organization|access-date=13 December 2016|url-status=dead|archive-url=https://web.archive.org/web/20161220180509/http://www.who.int/csr/research-and-development/list_of_pathogens/en/|archive-date=20 December 2016}}

In 2007, SIGA Technologies, studied a medication in guinea pig with Lassa fever.{{Cite web |url=https://www.reuters.com/article/idUSIN20070515084336SIGA20070515 |title=SIGA Technologies says passes first hurdle with lassa fever... |date=2007-05-15 |website=Reuters |language=en |access-date=2019-05-01 |archive-date=1 May 2019 |archive-url=https://web.archive.org/web/20190501083128/https://www.reuters.com/article/idUSIN20070515084336SIGA20070515 |url-status=live }} Work on a vaccine is continuing, with multiple approaches showing positive results in animal trials.{{Cite web|url=https://www.who.int/blueprint/what/research-development/Lassa_Virus_Vaccine_TPP.pdf?ua=1|title=WHO Target Product Profiles for Lassa virus Vaccine|date=April 2017|website=World Health Organization|access-date=11 September 2017|archive-date=28 August 2021|archive-url=https://web.archive.org/web/20210828140919/https://www.who.int/blueprint/what/research-development/Lassa_Virus_Vaccine_TPP.pdf?ua=1|url-status=live}}

{{Reflist}}

{{Portal|Viruses}}

• {{cite journal|last1=Echioya|first1=Deborah U.|first2=Meike|last2=Hass|first3=Stephan|last3=Olshlager|first4=Beate|last4=Becker-Ziaja|first5=Christian O. Onyebuchi|last5=Chukwu|first6=Jide|last6=Coker|first7=Abdulsalam|last7=Nasidi|first8=Osi-Ogdu|last8=Ogugua|first9=Stephan|last9=Gunther|first10=Sunday A.|last10=Omilabu|title=Lassa Fever, Nigeria, 2005-2008|journal=Emerging Infectious Diseases|year=2010|volume=16|issue=6|series=6|pages=1040–41|doi=10.3201/eid1606.100080 |pmid=20507773|pmc=3086228}}
• {{cite journal|last1=Branco|first1=Luis M.|first2=Jessica N.|last2=Grove|first3=Matt L.|last3=Boisen|first4=Jeffrey G.|last4=Shaffer|first5=Augustine|last5=Goba|first6=Mohammed|last6=Fullah|first7=Mambu|last7=Momoh|first8=Donald S.|last8=Grant|first9=Robert F.|last9=Garry|title=Emerging Trends in Lassa Fever: Redefining the Role of Immunoglobulin M and Inflammation in Diagnosing Acute Infection|journal=Virology Journal|date=4 October 2011|volume=8|page=478|doi=10.1186/1743-422x-8-478 |pmid=22023795|pmc=3223505 |doi-access=free }}

{{Medical resources

| ICD11 = {{ICD11|1D61.2}}

| ICD10 = {{ICD10|A96.2}}

| ICD9 = {{ICD9|078.8}}

| ICDO =

| OMIM =

| DiseasesDB = 7272

| MedlinePlus =

| eMedicineSubj =

| eMedicineTopic =

| MeshID = D007835

}}

{{Zoonotic viral diseases}}

{{DEFAULTSORT:Lassa Fever}}

Category:Arthropod-borne viral fevers and viral haemorrhagic fevers

Category:Biological agents

Category:Hemorrhagic fevers

Category:Rodent-carried diseases

Category:Tropical diseases

Category:Virus-related cutaneous conditions

Category:Zoonotic viral diseases

Category:Wikipedia medicine articles ready to translate

Category:Wikipedia infectious disease articles ready to translate