Epidemiologic and clinical features of lassa fever. The nigeria centre for disease control ncdc has said that these statistics should not mask the progress made in the control of lassa fever in the worlds worst hit country. Progress and challenges of lassa fever control in nigeria. International external quality assessment study for. Lassa virus, which spreads from rodents to humans, infecting about half a million people every year, can lead to deadly hemorrhagic fever. Current molecular epidemiology of lassa virus in nigeria. Pdf lassa virus is genetically diverse with several lineages. The disease was first described in nigeria in 1969. As of march 3, nigeria has confirmed 420 cases of lassa fever and 93 deaths in 2019, suggesting the 2018 record of the most cases reported in a single year will be surpassed. Lassa virus or lassa viral haemorrhagic fever is an acute illness of 14 weeks duration that occurs in west africa.
It is the causative agent of lassa fever, a potentially fatal viral hemorrhagic fever in humans for which only limited treatment options and no licensed vaccine are available. Full text current research for a vaccine against lassa. Mar 20, 2018 lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by the lassa virus lasv, a member of the family arenaviridae. Lassa fever is a viral illness that typically occurs in west africa. Lassa fever is an acute viral illness that occurs in west africa. This fairly common disease, endemic to west africa, is associated with significant morbidity and mortality in some cases, and is contagious. The natural host of lassa virus is the african rodent mastomys natalensis. The etiologic agent of lassa fever is lassa virus lasv, family arenaviridae, genus. Lassa fever is an acute viral haemorrhagic fever caused by lassa virus, a member of the arenavirus family. The most recent 2018 and 2019 nigerian outbreaks featured alarmingly high fatality rates of up to 25. Lamp1 increases the efficiency of lassa virus infection by. May 03, 2016 lassa virus lasv causes a deadly haemorrhagic fever in humans, killing several thousand people in west africa annually. However, the high degree of genetic variability of the virus poses a problem with the design of rtpcr assays that will reliably detect all strains.
Lassa virus lasv, a member of the family arenaviridae, is the causative agent of lassa fever. 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 to. It is an acute febrile viral illness lasting one to four weeks, and it occurs in west africa and some areas beyond. Structural basis for antibodymediated neutralization of lassa virus. Virus is shed in urine and droppings of the chronically infected animal host, the multimammate rat mastomys rodent species. Lassa virus lasv is endemic to parts of west africa and causes highly fatal hemorrhagic fever. Like many viruses, lassa virus binds to cell surface receptors. 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. A lassa fever liveattenuated vaccine based on codon. Lassa fever is a viral, hemorrhagic causes bleeding disease found in tropical regions of africa.
Pdf phylogeography of lassa virus in nigeria researchgate. In addition to the severity and high fatality of the disease, a significant population of survivors suffer from. Of 10 specimens captured in kako, southwestern nigeria, during this period, 4 were lasv positive table 1. Lassa fever virus lasv causes acute viral haemorrhagic fever with symptoms similar to those seen with ebola virus infections. Mastomys rats infected with lassa virus do not become ill, but they can shed the virus in their urine and faeces. Among them, the hemorrhagic fever virus lassa is responsible for 300,000500,000 infectionsy in western africa. Lassa virus lasv is endemic in western africa and is estimated to infect hundreds of thousands of individuals annually.
Details of lassa virus structure could inform development of. Lassa virus lasv 4 belongs to the old world clade of the family of arenaviridae. For the majority of lassa fever virus infections approximately 80%, symptoms are mild and are undiagnosed. Genomic analysis of lassa virus during an increase in. Lassa fever lf is a viral hemorrhagic disease caused by the lassa. The centers for disease control and prevention estimates that up to 300,000 lassa virus infections occur each year. Current research for a vaccine against lassa hemorrhagic fever virus bryce m warner,1 david safronetz,2 derek r stein2 1department of medical microbiology, university of manitoba, winnipeg, mb, canada. Lassa fever full recovery without ribavarin treatment. This page lists the evag products having been related to the lassa virus virus name. Abstract lassa fever is a viral hemorrhagic fever caused by lassa virus lassa mammarenavirus, a negativesense singlestranded rna virus of the arenaviridae family.
Lassa fever virus, a member of the family arenaviridae, is a highly endemic category a pathogen that causes 300,000500,000 infections per year in western africa. It may be fatal, but most patients recover from acute disease and some experience asymptomatic infection. Lassa mammarenavirus is an emerging virus and a select agent, requiring biosafety level 4equivalent containment. Lassa fever is caused by a virus that is found in west africa. Introduction to lassa fever generic presentation pdf, 1. There are differences in the virus particles and disease characteristics that influence the management of disease due to these 2 pathogens summarized in table 2. Lassa virus is an old world arenavirus, but several new world arenaviruses can cause vhf as well. Humans usually become infected with lassa virus from exposure to urine and faeces of infected mastomys rats. Nathnac lassa fever on the increase in west africa. Details about contact tracing were available for seven of the events.
Lassa mammarenavirus lasv is an arenavirus that causes lassa hemorrhagic fever, a type of viral hemorrhagic fever vhf, in humans and other primates. The goal of this project is to develop a small molecule inhibitor able to treat and prevent lassa fever as well as other arenavirus vhfs. Bibliometric analysis of global lassa fever research 1970. Pdf immunobiology of ebola and lassa virus infections. 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.
Lassa fever lf, or lassa hemorrhagic fever, is an infection caused by lassa virus lasv. The arenaviral nucleoprotein np has been implicated in suppression of the host innate immune system, but the mechanism by which this occurs has remained elusive. Pdf nigeria is presently suffering from another lassa fever epidemic. It is endemic in benin, ghana, guinea, liberia, mali, nigeria. Lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by the lassa virus lasv, a. Lassa fever, a viral haemorrhagic fever with symptoms similar to those of ebola virus disease, is endemic in much of west africa and usually sparks a seasonal outbreak from december to march. The bayesian analysis also provided estimates for divergence times within the lassa virus clade. Lassa fever is a frequently severe human disease that is endemic to several countries in west africa. Travelers to nigeria should avoid contact with rats, especially rat urine and feces, and keep their accommodations or campsites clean. The large amount of novel genomic diversity of lassa virus observed in the liberian cases emphasises the need to match deployed diagnostic capabilities with locally circulating strains and underscores the importance of evaluating crosslineage protection in the development of vaccines and therapeutics.
Lassa fever affects an estimated 300,000 people annually in the developing world, resulting in about 5,000 deaths. What you need to know about lassa fever 6 april 6 april 6 april 6 april 6 april 6 april 6 april estimated number of lassa fever cases in west africa each year death rate from ebola death rate from lassa fever estimated number of deaths lassa fever is caused by a virus that is found in west africa. The multimammate rat mastomys natalensis is the only known reservoir of lasv. Lassa fever and marburg fever are acute viral hemorrhagic illnesses. 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. Less commonly there may be bleeding from the mouth or gastrointestinal tract. Technical guidance on lassa fever general information. 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. Apr 20, 2020 nigerian health officials have declared an outbreak of lassa fever in nigeria.
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. Lassa fever is a disease that is spread primarily by rats. Varicella zoster virus structure of varicella zoster virus image source. Cases of lassa fever imported to europe indicate that the virus also circulates in ivory coast and mali 2, 9. More than 20 cases have been imported to the united states, canada, united kingdom and japan since 1969, when the disease was. Jan 23, 2017 two of the most important contemporary emerging viruses that affect human health in africa are ebola virus ebov and lassa virus lasv. An important component of any vaccine candidate against lassa virus will likely include the highly glycosylated glycoprotein complex presented on the virion surface. Lassavirus antigens were detected in the first serum sample from each patient, thus providing an early definitive diagnosis. Late rainy and early dry season affects all age groups and both sexes. A nanomicroarray for each gene of ebola, marburg, and lassa virus was designed, printed and evaluated. Guidance for contact tracing of cases of lassa fever.
Structure of the lassa virus nucleoprotein reveals a dsrna. Nigerian health officials have declared an outbreak of lassa fever in nigeria. Creative diagnostics varicellazoster virus vzv is an alphaherpesvirus that is in the same subfamily as herpes simplex virus hsv 1 and 2. Lassa virus, which is a member of the arenaviridae virus family, causes acute viral hemorrhagic fever. Lassa virus entry requires a triggerinduced receptor switch. Hospitalized patients with lf may pose a substantial risk to healthcare workers hcws and to other patients. When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. The search engine above will seek products into the complete catalogue. Jan 05, 2020 lassa virus is a singlestranded rna virus that is enveloped in lipid with glycoprotein spikes protruding from the outside surface. If you have problems viewing pdf files, download the latest version of adobe reader.
Multiplex detection of bioterrorism agents ebola, marburg. Mar 29, 2010 the method of choice for the detection of lassa virus is reverse transcription rtpcr. Lasv infection of humans can cause lassa fever lf, a disease associated with high morbidity and significant mortality. For language access assistance, contact the ncats public information officer. Lassa fever is caused by the lassa virus and it is endemic to a large region of west africa, where 100,000300,000 cases have been estimated to occur each year. Download acrobat pdf file 666kb multimedia component 1. The virus is a member of the arenavirus family and is spread primarily by rodents. Lassa fever onset begins with flulike symptoms and may develop into lethal hemorrhagic disease in severe cases. For 40 years, the natal multimammate rat, mastomys natalensis, has been assumed to be the sole host of lasv.
Development of a therapeutic for lassa fever national. It contains two species of rna called the small and large units and each unit has two. Lethal infection of lassa virus isolated from a human. 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. Lasv is endemic to west africa and is transmitted through contact with excretions of infected mastomys natalensis rodents and other rodent species. Signs and symptoms of lassa fever typically occur weeks after the patient comes into contact with the virus. A potent lassa virus antiviral targets an arenavirus. Lassa virus may be spread in contaminated medical equipment, such as reused needles. Many of those infected by the virus do not develop symptoms. Lassa fever is primarily spread from its rodent reservoir to humans, while humantohuman transmission occurs with low efficiency. Cette maladie a ete decouverte en 1969 lorsque deux infirmieres missionnaires sont mortes au nigeria.
How to safely collect blood samples by phlebotomy from patients suspected to be infected with lassa. How to extract and refine gold from old computer parts. Lassa virus, the causative agent of lassa fever, is a member of the family arenaviridae. Effective vaccine for lassa fever journal of virology asm. Less commonly there may be bleeding from the mouth or. Lassa virus lasv, the causative agent of lassa fever, is estimated to be responsible for up to 300,000 new infections and 5000 deaths each year across western africa. Infection with lassa virus in humans may take many forms. Lassa fever was first described in 1969 as the cause of a nosocomial outbreak of hemorrhagic fever in nigeria. Lassa virus is a highly pathogenic arenavirus that causes severe hemorrhagic fever in humans. Rapid detection and quantification of rna of ebola and. The disease is endemic in sierra leone, guinea, liberia, and nigeria 3, 6.
Lassa antibody and antigen were found in 96 11% and 46 5%, respectively, of 884 tested mastomys demby et al. The lassa virus is transmitted to humans mainly through handling rats, food or household items contaminated by rats urine and faeces. Partial gp sequences of these strains, labeled nig09ospmh86, 89, 123 and. Lassa virus is a singlestranded rna virus that is enveloped in lipid with glycoprotein spikes protruding from the outside surface. Lassa fever is an acute viral infection associated with a wide spectrum of disease manifestations, which range from mild courses to multiorgan failure. The virion is spherical in shape with icosahedral symmetry measuring 159200nm. Clinical research on lassa fever needs to integrate the priority of care and the imperative of research. An increase in lassa fever cases has been reported in west africa, with an outbreak currently reported in nigeria and cases in benin, ghana, guinea, liberia, and togo 14. 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. Pathogens free fulltext animal models of lassa fever. Lassa virus belongs to the old world complex of the family arenaviridae. The immune mechanisms associated with these different outcomes have not yet been fully elucidated, but considerable progress has recently been.
Improved detection of lassa virus by reverse transcription. Lassa fever is a viral illness that occurs in west africa. Lassa fever in nigeria, benin, togo, germany and usa reliefweb. 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 to global health. Lassa fever lf is a febrile infectious disease caused by lassa virus. Lassa fever, viral hemorrhagic fever, survival, ribavarin. Introduction to lassa fever world health organization. Lassa fever is a viral hemorrhagic fever that was first described in the town lassa in the northeast of nigeria 1, 2. Lassa fever is a zoonotic disease, meaning that humans become infected from contact with infected animals. Rapid detection and quantification of rna of ebola and marburg viruses, lassa virus, crimeancongo hemorrhagic fever virus, rift valley fever virus, dengue virus, and yellow fever virus by realtime reverse transcriptionpcr. Lassa virus lasv, the causative agent of lassa fever, is a negative strand rna virus belonging to the old world complex family arenaviridae characterized by the appearance of sandy ribosomes encapsulated in the virion as seen in electron. Lassa virus diversity and feasibility for universal. Lassa virus is the most clinically important member of the arenaviridae, a family that includes six additional biosafety level 4 bsl4 hemorrhagic fever viruses.
The additional filters enable you with creating a subselection of items of this list. The animal reservoir, or host, of lassa virus is a rodent of the genus mastomys, commonly known as the multimammate rat. 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. Recent lassa virus strains from nigeria were completely or partially sequenced. Due to a high fatality rate, lack of treatment options and difficulties with. Structure of the lassa virus glycan shield provides a. In october 2008 and march 2009, a preliminary screening for arenaviruses was conducted during the process of describing the african wood mouse h. Jan 08, 2011 san diego researchers take important step in developing vaccine for lassa virus duration. A considerable number of these infections result in lassa fever lf, which is associated with significant morbidity and a casefatality rate as high as 69% among hospitalized confirmed patients. Lassa virus entry requires a triggerinduced receptor. Two of the most important contemporary emerging viruses that affect human health in africa are ebola virus ebov and lassa virus lasv. Rodents, particularly mastomys natalensis, are considered the natural hosts of the virus.
Testing of samples for lassa virus should be performed under bsl4. Lassa fever is an illness caused by lassa virus, a singlestranded rna hemorrhagic fever virus from the family arenaviridae. Lassa fever is a hemorrhagic fever endemic to west africa and caused by lassa virus, an old world arenavirus. Lassa fever in nigeria watch level 1, practice usual. Glycoproteins on the surface of the virion form tshaped spikes extending 710 nm from the envelope. Lassa virus is endemic in west african countries, such as nigeria, guinea, liberia, and sierra leone, and causes outbreaks annually. The disease is mainly spread to humans through contamination with the urine or feces of infected rats 3,4. This requirement sheds light on the enigmatic resistance of bird cells. Immunobiology of ebola and lassa virus infections nature. The illness was discovered in 1969 when two missionary nurses died in nigeria.
Biochemical characterization of the lassa virus l protein. The nanomicroarray format was fabricated by printing autologous 4 capture oligonucleotides 1 to 4 located from four different regions in triplicate spots representing a typical virus pattern for ebola, marburg, and lassa as shown in figure 1a. Pathophysiology and treatment of lassa fever springerlink. Jun 02, 2017 lassa virus can cause a hemorrhagic disease called lassa fever and is endemic to western africa. Jun 27, 2014 lassa virus, which spreads from rodents to humans, infecting about half a million people every year, can lead to deadly hemorrhagic fever. The virus can spread between people through direct contact with the body fluids of a person infected with lassa fever, as well. Arenaviruses cause disease in industrialized and developing nations alike. Sequence variability and geographic distribution of lassa. It was first reported in 1969 in the town of lassa, in borno state, nigeria. Phylogenetic analysis revealed the predominance of lineage ii and iii strains, the existence of a previously undescribed sublineage in nigeria, and the directional spread of virus in the southern part of the country.
Outbreak of ebola virus disease in the lassa fever zone. 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. Currently, there are no efficacious vaccines or treatments available to combat this pathogen. Lassa fever clinical course and setting a standard of care. Natal multimammate mouse is the primary reservoir of lassa virus, found in subsaharan africa. The multimammate mouse mastomys natalensis is the only known nonhuman host for lassa virus monath et al. 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. National center for advancing translational sciences ncats, 6701 democracy.
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