Across 3 sequential crossborder lassa fever outbreaks identified in benin or togo between february 2017 and march 2019, the 3 countries improved their collection and sharing of patients crossborder travel histories, shortened the time between case identification and crossborder information sharing, and streamlined multinational coordination. Lassa fever lf is an acute and sometimes severe viral hemorrhagic illness endemic in west africa. Less commonly there may be bleeding from the mouth or gastrointestinal tract. The reservoir of the lassa virus is a rodent of the genus mastomys known as multimammate rat. An earlier description of a febrile syndrome in sierra leone was, in retrospect, very likely to have been the first account of lassa fever. An arenavirus was isolated from two of these patients and given the name of lassa virus after the town of lassa, nigeria, where the disease, known as lassa fever, occurred buckley et al. The history of recognized human arenavirus infection in africa began in 1969 with the mysterious death of two medical missionaries and the nearfatal illness. Lassa virus remains an important cause of illness in west africa and among the travelers returning from this region with an acute febrile illness. It was first described in northeastern nigeria in 1969, and it is endemic in west africa 1.
Lassa fever lf is endemic to nigeria, where the disease causes substantial rates of illness and death. It is spread by contact with infected rats or objects contaminated by them, or persontoperson through transfer of secretions or excretions. Jan 21, 2016 lassa fever is an acute viral illness that occurs in west africa. Neighboring countries are also at risk, as the animal vector for lassa virus, the multimammate rat mastomys natalensis is distributed throughout the region. Lassa fever or lassa hemorrhagic fever lhf is an acute viral hemorrhagic fever caused by the lassa virus and first described in 1969 in the town of lassa, in borno state, nigeria. Obtain information about the patients occupation, history of travel outside the united. Lassa fever is a hemorrhagic viral disease caused by the lassa virus lasv, a member of the arenaviridae family from the arenavirus genus, and is transmitted to humans by some rodents. Lassa fever full recovery without ribavarin treatment. Aug 23, 2018 lassa fever is a viral hemorrhagic fever caused by an rna virus of the arenavirus family. Lassa fever is an acute viral illness that occurs in west africa. Lassa fever is endemic in most parts of sierra leone. The illness was discovered in 1969 when two missionary nurses died in nigeria.
A major difference between ebola and lassa fever is the manner in which they are transmitted. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria. The risk of getting lassa fever in the united states is extremely low signs and symptoms of lassa fever are usually mild lassa fever can be treated if a healthcare worker suspects lassa fever in a patient, a laboratory test can diagnose the disease. Development of a therapeutic for lassa fever national. History of recent contact with a probable or confirmed case of lassa fever within 21 days of onset of fever c. Pdf on jan 1, 2018, aude lalis and others published mice and men. Less commonly there may be bleeding from the mouth or. Brief history, diagnosing, and symptoms of lassa fever. Epidemiology and control of lassa fever springerlink. Highly recommended account of virology before the catchphrase emerging infection was coined, before bsl4 facilities and physicians worrying about themselves. Lassa virus is diagnosed by doing a laboratory test in a test centre. It is widespread in many african countries, such as liberia and sierra leone, and it can be fatal.
In this article, we report an analysis of the epidemiologic and clinical aspects of the lf outbreak that occurred in nigeria during january 1may 6, 2018. This is in addition to the concurrent response to other epds such as measles, cerebrospinal meningitis, monkeypox, cholera and viral haemorrhagic fevers such as. Lassa fever in west africa journal of advances in medicine and. In 2004, the centers for disease control and prevention cdc reported a fatal case of lassa fever in new jersey. Difference between ebola and lassa fever ebola vs lassa. The animal reservoir of the lassa fever virus is a rat, mastomys natalensis. Presently, lassa fever management involves the use of ribavarin, supportive therapy, and simple barrier nursing usually in a specific ward dedicated for the disease 6. Lassa fever outbreak in nigeria, worst in history, kills 78. Deadly lassafever outbreak tests nigerias revamped. A report by the nigeria center for disease control ncdc on march 4 indicated a mortality rate of 23.
Information for this disease was retrieved from the technical working group and situation reports. A suspected case of lf was defined as illness meeting 1 of the following criteria. Mar 15, 2018 deadly lassafever outbreak tests nigerias revamped health agency. The lassa virus is transmitted to humans mainly through food or household items contaminated by infected rats urine and faeces and by handling infected rats.
Lassa fever is a zoonotic disease, meaning that humans become infected from contact with infected animals. Lassa fever is a viral, hemorrhagic causes bleeding disease found in tropical regions of africa. Epidemiologic and clinical features of lassa fever. Lassa fever is a viral disease spread by the the multimammate rat. Mastomys rats infected with lassa virus do not become ill, but they can shed the virus in their urine and faeces. It is endemic to west africa, spread by the multimammate rat that abounds in the region and is sometimes eaten as bushmeat. Health workers may be infected by direct contact with blood, body fluids, urine, or stool of a patient with lassa fever. The exposure is usually to a multimammate rat mastomys natalensis. The ebola virus is mainly carried by fruit bats and can be transmitted through close contact with the blood, secretions, organs or other bodily fluids of the bat, or any other animalperson it may have infected. 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 a zoonotic disease that commonly manifests as an acute viral hemorrhagic fever. Lassa fever is an acute viral illness, transmitted to humans by rodents. Lassa fever is one of the hemorrhagic fever viruses, occurring in west africa subregions in similar areas as ebola virus. Ribavirin, an antiviral drug, has been used to successfully treat patients with lassa fever.
The next year i entered graduate school to earn a ph. Lassa fever is named for the town in ghana near where it was first identified as a unique viral illness in 1969. Primary transmission can be prevented by avoiding contact with mastomys rodents, especially in regions where outbreaks occur. Although the lassa fever was described for the first time in the 1950s, the virus responsible was only isolated in 1969 during an epidemic in lassa village in.
Most cases are caused by infection from ingestion, inhalation, or direct contact with the environmental reservoir, mastomys natalensis rodents. Lassa fever in the netherlands ex sierra leone ecdc. Early attempts at treating lassa fever involved total isolation and supportive therapy with or without the use of the convalescent serum or antibody 5, 6. Favipiravir and ribavirin treatment of epidemiologically. In lassa fever endemic regions such as nigeria, a suspected case is defined 23 as an illness.
A free powerpoint ppt presentation displayed as a flash slide show on id. The areas where lassa is found are the areas where this rat is found. Benin was last affected by lassa fever over a 4 monthperiod in 20142015 when 16 cases were reported and 9 people died. The disease was first recognized in nigeria in 1969. Lassa fever european centre for disease prevention and. Lassa antibody and antigen were found in 96 11% and 46 5%, respectively, of 884 tested mastomys demby et al.
Lesson learned from the investigation and response of lassa fever. Ppt lassa fever powerpoint presentation free to view. Lassa fever european centre for disease prevention and control. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever. Historical lassa fever reports and 30year clinical. Laboratory diagnosis of lassa fever journal of clinical. Nigerians adopt preventive measures as lassa fever.
In its severest form, if it is not treated, the disease can lead to death. Introduction to lassa fever world health organization. Lassa virus is a member of the old world arenaviruses, and, as such, is endemic in western africa. Lassa fever is named after the town in northeastern nigeria in which it was discovered in 1969. The world report by talha burki feb 24, p 7281 described an unprecedented astronomical rise in lassa fever cases in nigeria, for which the first case was reported in 1969 and the epidemiology and endemicity are well understood. Symptoms include fever and damage to multiple organs and the circulatory system. Benin was last affected by lassa fever over a 4 monthperiod in 20142015 when 16. Lassa fever in nigeria, benin, togo, germany and usa reliefweb.
The disease was first described in the 1950s, and the virus was identified in 1969 after 2 missionary nurses died from the disease in the nigerian. A history of contact with excreta of rodents or with a probable or confirmed case of lassa fever. Historical lassa fever reports and 30year clinical update. Epidemiologic and clinical features of lassa fever outbreak. Isolating the virus from blood, urine, or throat washings. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. Late rainy and early dry season affects all age groups and both sexes 3. Lassa virus, the causative agent of lassa fever, is a member of the family arenaviridae.
Lassa fever causes, symptoms, treatment, diagnosis and. Lassa fever has a mortality rate of 1% for all those infected with the virus. The arenaviruses cause the diseases lassa fever lassa virus. It is a viral haemorrhagic fever in the same family as ebola. General facts viral hemorrhagic fever caused by the arenavirus lassa transmitted from rodents to humans discovered in nigeria, 1969 endemic in portions of west africa seasonal clustering.
A historical look at the first reported cases of lassa. Lassa fever is a viral hemorrhagic fever caused by a rodentborne arenavirus that is endemic in west africa. Lassa fever was one of the first three diseases they chose to seek a vaccine against, because they felt it was so threatening. Who target product profiles for lassa virus vaccine pdf. A historical look at the first reported cases of lassa fever.
Jun 27, 2018 lassa fever is a viral disease spread by the the multimammate rat. Mar 28, 2019 lassa fever is named for the town in ghana near where it was first identified as a unique viral illness in 1969. The rate jumps to 15% for all those who are infected and are hospitalized. How to diagnose lassa fever lassa virus can be diagnosed in three ways. Lassa fever disease lassa fever is viral illness that occurs in west africa.
Lassa fever symptoms, diagnosis and treatment bmj best. Demonstrating the presence of immunoglobuline m igm antibody to lassa virus. Viral hemorrhagic fever caused by the arenavirus lassa. Researchers in nigeria are racing to identify cases of lassa fever and to understand why the ongoing. Lassa fever outbreak in nigeria, worst in history, kills. In line with this, the ncdc has been leading the public health response to the ongoing the coronavirus disease covid19 outbreak in nigeria. Ribavirin is occasionally used for postexposure prophylaxis. It occurs in west africa, mainly in nigeria, sierra leone, liberia, guinea. This course provides a general introduction to lassa fever and is intended for personnel responding to outbreaks in complex emergencies or in settings where the basic environmental. It is most common in a large region of west africa, and is named after the nigerian town where it was. Although importation of lassa fever to nonendemic countries is a rare event, it has repeatedly happened over five decades. The two imported cases of lassa fever recently reported from togo.
Suspicion of lassa fever should be based on careful consideration of clinical features and exposure history in order to assist early diagnosis in returning travellers from west africa. Deadly lassafever outbreak tests nigerias revamped health agency. Feb 06, 20 lassa fever lf is an acute and sometimes severe viral hemorrhagic illness endemic in west africa. Retrospective case history indicated that this patient also had onset of symptoms on. Patient with history of fever and history of travel to high riskburden area. Lassa virus may also be spread between humans through direct contact with the blood, urine, faeces, or other bodily secretions of a person infected with lassa fever. Lassa fever lf is a viral hemorrhagic disease caused by the lassa virus lasv and endemic in west. Lassa fever is on the rampage again in nigeria, but there are simple steps that can be taken to prevent infection. Lassa fever, a significant cause of morbidity and mortality, while lassa fever is mild or has no observable symptoms in about eighty per cent of people infected with lassa virus. Lassa fever is one of the hemorrhagic fever viruses like ebola virus, marburg virus, and others unlike ebola virus, lassa fever is not as contagious person to person, nor as deadly lassa virus is typically transmitted by the urine or feces of mastomys rats to humans. However, the full extent of lassas endemicity is unknown due to poor mean of contact and communication with the rural villages where lassa is surely seen, a factor that prevents both reporting and treatment of infection. Mar 16, 2018 lassa fever has a mortality rate of 1% for all those infected with the virus. The history of recognized human arenavirus infection in africa began in 1969 with the mysterious death of two medical missionaries and the nearfatal illness of a third frame et al. The virus is named after the town in nigeria where.
Lassa fever is a member of the arenaviridae virus family. Management involves early initiation of ribavirin with supportive care in a hospital setting. The symptoms of lassa fever can be nonspecific and mimic those of other endemic infections, especially early in illness, making a clinical diagnosis difficult. Each year, an estimated 300,000 people are infected, and severe cases can be fatal. The multimammate mouse mastomys natalensis is the only known nonhuman host for lassa virus monath et al. History of lassa fever in nigeria lassa fever was first given medical description in the 1950s but the causative viral particle was first identified in 1969 from three missionary nurses who fell ill and died after caring for an infected obstetrical patient in the town of lassa, borno state, nigeria, west africa. Failure of the nigerian health system to prioritise preparedness activities has been detrimental for prompt control of lassa fever, which requires robust laboratory.
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