Clinical sequencing uncovers origins and evolution of lassa virus. Clinical sequencing uncovers origins and evolution of. A historical look at the first reported cases of lassa fever. Against the backdrop of the raging lassa fever virus, the redeemers university, run, ede, osun state, has developed a test kit known as panlassa rapid diagnostics test pl. Lassa fever is a viral illness that originated in west africa in 1969. Jun 27, 2014 the lassa virus, endemic to west africa, uses an unexpected twostep process to enter cells, research has shown. Pathophysiology and treatment of lassa fever springerlink.
Lassa fever simple english wikipedia, the free encyclopedia. Lassa virus is an arenavirus transmitted to humans by inhalation of or exposure to mastomys natalensis excreta, but it can also be transmitted persontoperson through virusinfected bodily fluids. Sufficient capacity exists in the eu for testing purposes, however given the wide genetic diversity of circulating lassa viruses, laboratory protocols. Structure lysogenic vs lytic airborne transmitted virus mastomys rodents urine or droppings person to person blood body. 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. The centers for disease control and prevention estimates that up to 300,000 lassa virus infections occur each year. Many of those infected by the virus do not develop symptoms. Redeemers varsity develops 10mins lassa fever testkit. Clinical research on lassa fever needs to integrate the priority of care and the imperative of research. Lassa fevercaused by infection with the lassa virusis named after the town in nigeria where the first identified cases occurred. Jun 02, 2017 lassa virus can cause a hemorrhagic disease called lassa fever and is endemic to western africa.
Mar 14, 2016 lassa fever infects an estimated 100,000 to 300,000 individuals in west africa each year and around 5,000 result in death. Lassa virus, the causative agent of lassa fever, is a member of the family arenaviridae. Lassa fever in nigeria, benin, togo, germany and usa reliefweb. The lassa virus, endemic to west africa, uses an unexpected twostep process to enter cells, research has shown. May 03, 2016 lassa virus lasv causes a deadly haemorrhagic fever in humans, killing several thousand people in west africa annually. Lassa virus has ancient origins in modernday nigeria and has recently spread across west africa. Lassa virus or lassa viral haemorrhagic fever is an acute illness of 14 weeks duration that occurs in west africa. Caused by lassa virus lasv, the disease is a scourge on populations in endemic. Lassa virus infection occurs through contact with the vector mastomys natalensis or infected.
Lesson learned from the investigation and response of lassa fever. The results suggest that the mechanism by which lassa virus causes infection is. African countries with an estimation of 300,000 to 500,000 cases and 5,000 deaths annually. Case of human lassa virus infection with robust acute tcell. The lack of specific antiviral therapies for lassa fever drives an urgent need to identify druggable targets, and interventions that block infection at the entry stage are particularly attractive. Less commonly there may be bleeding from the mouth or gastrointestinal tract. Pathogenesis of lassa fever in cynomolgus macaques. Lassa antibody and antigen were found in 96 11% and 46 5%, respectively, of 884 tested mastomys demby et al. Details of lassa virus structure could inform development of.
In october 2008 and march 2009, a preliminary screening for arenaviruses was conducted during the process of describing the african wood mouse h. Lassa virus definition of lassa virus by medical dictionary. To date, no licensed vaccines are available to prevent lassa virus lasv infection, even though lassa fever is thought to be an important disease contributing to mortality and both acute and chronic morbidity. Lassa fever in nigeria watch level 1, practice usual. Such infections are often asymptomatic, but in those who become ill, the disease can range from an uncomplicated fever of unknown origin to a fulminating hemorrhagic disease. Baseline mapping of lassa fever virology, epidemiology and. Dec, 2016 lassa fever, marburg virus disease and ebola virus disease are all viral haemorrhagic fevers.
However, their contagiousness means that the potential for outbreak is real if imported cases go undetected. Protection from lethal lassa disease can be achieved both. Lassa fever is a viral illness that occurs in west africa. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria. The center of disease control and prevention has confirmed a case of lassa fever at emory university hospital. Apr 20, 2020 nigerian health officials have declared an outbreak of lassa fever in nigeria. It is endemic in west african countries, especially sierra leone, the republic of guinea, nigeria, and liberia, where the annual incidence of infection is between 300,000 and 500,000 cases, resulting in 5,000 deaths per year.
The arenavirus lassa causes severe hemorrhagic fever and a significant disease burden in west africa every year. Infection with lassa virus in humans may take many forms. Introduction to lassa fever world health organization. A 10year lassa virus research project has yielded structural and functional details of a key viral surface protein that could help advance development of lassa vaccines and antibodybased. Lassa virus lasv is a member of the old world complex of viruses, genus arenavirus, family arenaviridae, which also includes lymphocytic choriomeningitis virus lcmv and lujo virus. Increasing evidence of emerging and reemerging zoonotic diseases including recent lassa fever outbreaks in almost 20 states in nigeria led to 101 deaths and 175 suspected and confirmed. Lassa mammarenavirus lasv is an arenavirus that causes lassa hemorrhagic fever, a type of viral hemorrhagic fever vhf, in humans and other primates. The lassa virus is transmitted to humans mainly through handling rats, food or household items contaminated by rats urine and faeces. Natal multimammate mouse is the primary reservoir of lassa virus, found in subsaharan africa. At ph, six of 52 consecutive febrile patients had lf. The virus is found in west africa in areas overlapping with the geography of its animal reservoir. This was confirmed in the statement of the minister of health of the federation. Village surveys in kolahun district showed prevalences of lassa virus antibodies of 6.
Lassa fever clinical course and setting a standard of care. Nigerian health officials have declared an outbreak of lassa fever in nigeria. Lassa mammarenavirus is an emerging virus and a select agent, requiring biosafety level 4equivalent containment. Pdf nigeria is presently suffering from another lassa fever epidemic. International external quality assessment study for.
Lassa fever is an acute viral infection associated with a wide spectrum of disease manifestations, which range from mild courses to multiorgan failure. Lassa fever is an animalborne, or zoonotic, acute viral illness. Lassa virus is a virulent and highly transmissible rna virus that belongs to the arenavirus group. Outside of the case at emory university hospital, there have been six other cases of lassa fever reported in the united states. Apr 28, 2018 we evaluated the impact of manmade conflict events and climate change impact in guiding evidencebased community one health epidemiology and emergency response practice against reemerging epidemics. The natural reservoir of the lassa virus is the multimammate rat mastomys natalensis, a rodent found commonly in rural areas of tropical africa that often colonises in or around human homes where food is stored. This work illuminates phdriven conformational changes in both receptorbinding and fusion subunits of lassa virus, illustrates the unique assembly of the arenavirus glycoprotein spike, and provides a muchneeded template for vaccine design against these threats. Lassa fever is an illness caused by lassa virus, a singlestranded rna hemorrhagic fever virus from the family arenaviridae. Lassa fever is a frequently severe human disease that is endemic to several countries in west africa. While ebov and lasv were both discovered in the latter part of the 20th century1976 and 1969, respectivelytheir origins likely vary greatly commission, 1978, frame et al. Cases of lassa fever in the netherlands ex sierra leone ecdc.
Six cynomolgus monkeys were experimentally infected with lasv. Lassa fever is a viral haemorrhagic fever caused by lassa virus belonging to arenaviridae family and is endemic in west african countries of sierra leone, liberia, guinea and nigeria. Lassa fever lf is a viral hemorrhagic disease caused by. Of 10 specimens captured in kako, southwestern nigeria, during this period, 4 were lasv positive table 1. Lassa fever lf is an acute and sometimes severe viral hemorrhagic illness endemic in west africa. Once infected, this rodent is able to excrete virus in urine.
Download acrobat pdf file 666kb multimedia component 1. This article is from plos neglected tropical diseases, volume 8. Lassa virus lasv infection causes an acute and sometimes fatal hemorrhagic disease in humans and nonhuman primates. 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. Lassa virus is a member of the old world arenaviruses, and, as such, is endemic in western africa.
Jul 12, 2017 lassa fevercaused by infection with the lassa virusis named after the town in nigeria where the first identified cases occurred. Lamp1 increases the efficiency of lassa virus infection by. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. Lassa virus diversity and feasibility for universal. The reservoirs of all three diseases are mainly confined to equatorial africa. Lassa fever was discovered in 1969 after two nurses died from the disease. The very diverse lasv genome has 4 major lineages associated with different geographic locations. Some cases are severe and require going to a hospital.
Lassa virus lasv is unique among bl4 agents in being a common human pathogen, causing endemic disease in much of west africa, primarily in sierra leone, guinea, liberia, and nigeria figure 1a. Lassa is named after the town in which it was discovered. Lassa virus was first isolated in 1974 from its zoonotic reservoir, the multimammate rat mastomys natalensis. Viruses that cause human hemorrhagic fevers, such as ebola, marburg and lassa, are classified as bl4 agents due to their high fatality rates and lack of effective. Feb 06, 20 lassa fever lf is an acute and sometimes severe viral hemorrhagic illness endemic in west africa. The virus can spread between people through direct contact with the body fluids of a person infected with lassa fever, as well. Lassa fever is a virus disease of man characterized by generalized organ involvement resulting in manifestations of myositis, myocarditis, pneumonitis, encephalopathy, and.
Lasv infection of humans can cause lassa fever lf, a disease associated with high morbidity and significant mortality. The etiologic agent of lassa fever is lassa virus lasv, family arenaviridae, genus. Lassa fever is a disease that is spread primarily by rats. It was first reported in 1969 in the town of lassa, in borno state, nigeria. Here, we performed a pilot study to begin to understand the progression of lasv infection in nonhuman primates. Six cynomolgus monkeys were experimentally infected with. Travelers to nigeria should avoid contact with rats, especially rat urine and feces, and keep their accommodations or campsites clean.
Lassa fever by carly brown discovery john frame 1969 collaborated with yale arbovirus research unit typestructure arenaviridae family spherical lipid membrane singlestranded rna transportation zoonotic hostmultimammate rat genus mastomys person to person transportationcont. Niger delta journal of medicine and medical research 20, 1 1. Increasing evidence of emerging and reemerging zoonotic diseases including recent lassa fever outbreaks in almost 20 states in nigeria led to. We evaluated the impact of manmade conflict events and climate change impact in guiding evidencebased community one health epidemiology and emergency response practice against reemerging epidemics. Most human infections result from zoonotic transmission. Lassa virus is the most clinically important member of the arenaviridae, a family that includes six additional biosafety level 4 bsl4 hemorrhagic fever viruses. Who has identified lassa virus as one of the viruses that is likely to cause a future epidemic, although a. Virus is shed in urine and droppings of the chronically infected animal host, the multimammate rat mastomys rodent species. The reservoir, or host, of lassa virus is a rodent known as the multimammate rat mastomys natalensis. Lassa virus was discovered in 1969 by a team led by dr. Eu for testing purposes, however given the wide genetic diversity of circulating lassa viruses, laboratory protocols for rtpcr detection. The glycoprotein, gpc, is the sole antigen expressed on the viral surface and the critical target for antibodymediated neutralization. Health workers may be infected by direct contact with blood, body fluids, urine, or stool of a patient with lassa fever. 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 lf, an oftenfatal hemorrhagic disease caused by lassa virus. Infection with lasv can lead to acute lassa fever lf with symptoms similar to evd. 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. Lassa virus is a singlestranded rna virus that is enveloped in lipid with glycoprotein spikes protruding from the outside surface. Late rainy and early dry season affects all age groups and both sexes 3. Current and historical conditions indexed list of current and historical nationally notifiable conditions. Sequence variability and geographic distribution of lassa. A historical look at the first reported cases of lassa. Lassa virus lasv is a highly prevalent mammarenavirus in west africa and is maintained in nature in a persistently infected rodent host, mastomys natalensis, which is widely spread in subsaharan africa. It is an acute febrile viral illness lasting one to four weeks, and it occurs in west africa and some areas beyond. Lassa fever was first described in 1969 as the cause of a nosocomial outbreak of hemorrhagic fever in nigeria.
When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. Most current vaccine candidates use only lineage iv antigens encoded by lassa viruses circulating around sierra leone, liberia, and guinea but. Lassa fever, marburg and ebola virus doctor patient. For 40 years, the natal multimammate rat, mastomys natalensis, has been assumed to be the sole host of lasv. Lassa fever is a viral illness that typically occurs in west africa.
High crossreactivity of human t cell responses between lassa virus. The multimammate rat mastomys natalensis is the only known reservoir of lasv. The multimammate mouse mastomys natalensis is the only known nonhuman host for lassa virus monath et al. The virus is a member of the arenavirus family and is spread primarily by rodents. To date no lasv vaccine candidates have undergone clinical evaluation. Pdf immunobiology of ebola and lassa virus infections. Abstract lassa fever is a viral hemorrhagic fever caused by lassa virus lassa mammarenavirus, a negativesense singlestranded rna virus of the arenaviridae family. Case of human lassa virus infection with robust acute t.
The reservoir of the lassa virus is a rodent of the genus mastomys known as. Lassa virus, which is a member of the arenaviridae virus family, causes acute viral hemorrhagic fever. Two of the most important contemporary emerging viruses that affect human health in africa are ebola virus ebov and lassa virus lasv. Unless you live in or have visited certain parts of western africa, or have had close contact with someone who does or has, your likelihood of contracting lassa fever is very low. Lassa virus consists of four lineages, which have a strain variation of 27% in relation to their nucleotides and 15% in relation to their amino acids. Lassa virus lasv is endemic to parts of west africa and causes highly fatal hemorrhagic fever. Details of lassa virus structure could inform development. The first challenge is biosafety, as the lassa virus belongs to the group 4 of dangerous pathogens and therefore needs to be handled in at least biosafety level 3 bsl3 laboratories. Pathogenesis of lassa fever in cynomolgus macaques virology. Lassa virus can cause a hemorrhagic disease called lassa fever and is endemic to western africa. Jan 31, 2019 lassa virus lasv is a highly prevalent mammarenavirus in west africa and is maintained in nature in a persistently infected rodent host, mastomys natalensis, which is widely spread in subsaharan africa.
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