It is endemic in west african countries, especially sierra leone, the republic of guinea, nigeria, and liberia, where the annual. Neighboring countries are also at risk, as the animal vector for lassa virus, the multimammate rat mastomys natalensis is distributed throughout the region. We developed a replicationcompetent vaccine against lassa virus. The center of disease control and prevention has confirmed a case of lassa fever at emory university hospital. A potent lassa virus antiviral targets an arenavirus. Current and emerging strategies for the diagnosis, prevention and.
Mass media awareness campaign and the prevention of the spread. The method of choice for early detection of lasv in blood is rtpcr. Lassa virus prevention in west africa great problem seminar. To facilitate the functional analysis of this virus, a replicon system was developed based on lassa virus strain av. Centers for disease control and prevention office of public health scientific services ophss center for surveillance, epidemiology, and laboratory services csels. The lassa virusspecific cd8 tcell responses at the convalescent time point were dominated by polyfunctional cells, with approximately 75% of the lassa virusspecific cd8 t cells expressing 1 cytokine upon stimulation. Most human infections result from zoonotic transmission. Lassa fever is a viral hemorrhagic fever caused by a rodentborne arenavirus that is endemic in west africa. Author summary lassa fever is a viral hemorrhagic fever disease that is transmitted to humans primarily through contact with the urine or feces of infected rodents.
Case of human lassa virus infection with robust acute tcell. Details of lassa virus structure could inform development of. The different lasv strains are grouped into lineages based on the geographical location of the isolated strains. Lassa virus lasv is endemic to parts of west africa and causes highly fatal hemorrhagic fever. 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. Jun 02, 2017 lassa virus can cause a hemorrhagic disease called lassa fever and is endemic to western africa. However, their contagiousness means that the potential for outbreak is real if imported cases go undetected. Virus pathogen database and analysis resource vipr. Lassa virus is one of more than 25 causative viruses of viral hemorrhagic fever table 4. Lassa fever is a member of the arenaviridae virus family. Lassa mammarenavirus lasv is an arenavirus that causes lassa hemorrhagic fever, a type of viral hemorrhagic fever vhf, in humans and other primates. The patient needs to be kept in isolation, and anyone in contact with him must use barrier protections like masks, gloves, gowns, and goggles.
Lassa fever lf is an endemic west african viral hemorrhagic fever which presents acutely and is often fatal. It is most common in a large region of west africa, and is named after the nigerian town where it was. See the editorial commentary by fischer and wohl on pages 177981. Lassa virus is a virulent and highly transmissible rna virus that belongs to the arenavirus group. Lassa fever is an acute viral infection associated with a wide spectrum of disease manifestations, which range from mild courses to multiorgan failure. Antiviral treatment of lassa fever is limited to offlabel use of ribavirin, which was. Determining ribavirins mechanism of action against lassa. May 26, 2015 lassa fever is common in west africa and can cause similar symptoms as ebola. Abstract lassa fever lf is a potentially fatal disease that affects an. Only about 20% of people with lassa fever develop symptoms. Vaccine platforms for the prevention of lassa fever sciencedirect. Lassa virus is a singlestranded rna virus that is enveloped in lipid with glycoprotein spikes protruding from the outside surface. The centers for disease control and prevention estimates that up to. Viruses, arenavirus, lassa fever, lassa virus, rodentborne infections, mastomys natalensis, field studies, mali, dispatch lassa fever is an acute viral infection associated with a wide spectrum of disease manifestations, which range from mild to hemorrhagic fever characterized by multiorgan failure 1.
Sep 15, 2017 lassa fever lf is a severe and often fatal hemorrhagic disease caused by lassa virus lasv, a member of the arenaviridae virus family. Lassa virus was discovered in 1969 by a team led by dr. A companion article in journal of infectious diseases describes the immune response to lassa virus seen in one of the patients. Who target product profile for lassa virus vaccine world health.
Putting food away in rodentproof containers and keeping the home clean help to discourage rodents from entering homes. Lassa fever is a hemorrhagic viral disease endemic to west africa. For testing pcr sensitivity, vero cells were infected with lassa virus or lcmv at a multiplicity of infection of 0. Lassa fever, marburg and ebola virus doctor patient. Knowledge attitude and practices toward lassa fever control. Centers for disease control and prevention office of public health scientific services ophss center for.
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. The reservoirs of all three diseases are mainly confined to equatorial africa. Lassa virus lasv is responsible for a type of acute viral haemorrhagic fever referred to as lassa fever. Primary transmission of the lassa virus from its host to humans can be prevented by avoiding contact with mastomys rodents, especially in the geographic regions where outbreaks occur. The case fatality rate was 25% among confirmed cases, underscoring the need for an effective antiviral therapy. The virus is found in west africa in areas overlapping with the geography of its animal reservoir. Lassa fever was first described in 1969 as the cause of a nosocomial outbreak of hemorrhagic fever in nigeria. There is a need for more information on kinetics of lassa virus detection in blood and nonblood. Genetic characterization of lassa virus strains isolated from.
Avoidance of contact with infected material in endemic areas and during care of affected patients suggested reading 1. 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. Ribavirin is the only medical countermeasure known to be effective against lassa virus, which is estimated to infect 100,000 to 300,000 people per year in west africa. Lassa virus lasv is the causative agent of lassa fever lf, a viral hemorrhagic fever with manifestations that range from asymptomatic to an acute, severe form associated with significant mortality up to 50% in hospitalized patients 1, 2. It is a singlestranded rna virus of the arenaviridae family, and it is animal borne. Health workers may be infected by direct contact with blood, body fluids, urine, or stool of a patient with lassa fever. 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 etiologic agent of lassa fever is lassa virus lasv, family arenaviridae, genus arenavirus. Assessment of the level of knowledge and universal cross. Adults can take 2 gm of ribavirin as a first dosage, followed by 1 gm every six hours for four days. Lassa mammarenavirus is an emerging virus and a select agent, requiring biosafety level 4equivalent containment. Natal multimammate mouse is the primary reservoir of lassa virus, found in subsaharan africa. The results suggest that the mechanism by which lassa virus causes infection is. This study assessed the knowledge, attitude, and practices toward lassa fever control and prevention among residents of ileife, southwest nigeria. Lassa virus, which is a member of the arenaviridae virus family, causes acute viral hemorrhagic fever. Rtpcr assay for detection of lassa virus and related old. The multimammate rat mastomys natalensis is the only known reservoir of lasv. Mar 25, 2014 primary transmission of the lassa virus from its host to humans can be prevented by avoiding contact with mastomys rodents, especially in the geographic regions where outbreaks occur.
Less commonly there may be bleeding from the mouth or. Lassa fever is an animalborne, or zoonotic, acute viral illness. Lassa virus definition of lassa virus by medical dictionary. Pdf immunoinformaticsguided designing of peptide vaccine. 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. Participating laboratories may use results of lassa virus eqa to. International external quality assessment study for molecular.
Sequence variability and geographic distribution of lassa. This is because the popular carriertransmitter of the lassa virus. Genetic characterization of lassa virus strains isolated. Mar 28, 2019 when a person who may have lassa fever seeks medical attention, proper transmission prevention measures must be taken. Mar 14, 2016 the center of disease control and prevention has confirmed a case of lassa fever at emory university hospital. The disease is endemic in west africa, and an unusually large outbreak occurred in nigeria in early 2018. In october 2008 and march 2009, a preliminary screening for arenaviruses was conducted during the process of describing the african wood mouse h. Lassa is named after the town in which it was discovered. Usually, each year sees only a smattering of cases reported, but. Lassa fever is an illness caused by lassa virus, a singlestranded rna hemorrhagic fever virus from the family arenaviridae. Though first described in the 1950s, the virus causing the disease was not. Jun 27, 2014 the lassa virus, endemic to west africa, uses an unexpected twostep process to enter cells, research has shown.
Historical lassa fever reports and 30year clinical update. Current research for a vaccine against lassa hemorrhagic. Case of human lassa virus infection with robust acute t. 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. Details of lassa virus structure could inform development. We report the isolation and genetic characterization of lassa virus from an area previously unknown for lassa fever. The aim of our study was to characterize the lineage ii strains in southern nigeria. To determine whether lassa virus was circulating in southern mali, we tested samples from small mammals from 3 villages, including soromba, where in 2009 a british citizen probably contracted a lethal lassa virus infection. Lassa fever is a viral illness that originated in west africa in 1969.
Development of a new vaccine for the prevention of lassa fever. Lassa fever in the same family of viruses as the ebola virus. It was first reported in 1969 in the town of lassa, in borno state, nigeria. Lack of adequate treatment and preventive measures against lasv resulted in a high. Lassa virus can cause a hemorrhagic disease called lassa fever and is endemic to western africa. Both diseases can cause haemorrhaging and can spread through contact with infected bodily fluids, though this is. Lassa fever had been reported as a cause of death especially in endemic parts of nigeria.
In 2004, the centers for disease control and prevention cdc reported a fatal case of lassa fever in new jersey. Many of those infected by the virus do not develop symptoms. Knowledge attitude and practices toward lassa fever. Proper sterilization of surfaces and equipment is likewise required. The very diverse lasv genome has 4 major lineages associated with different geographic locations. Dec, 2016 lassa fever, marburg virus disease and ebola virus disease are all viral haemorrhagic fevers. Pregnant women are particularly at risk from the virus. Virus strains used for the study are summarized in table 1. It is an acute febrile viral illness lasting one to four weeks, and it occurs in west africa and some areas beyond. The virus is a member of the arenavirus family and is spread primarily by rodents. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. 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. The etiologic agent of lassa fever is lassa virus lasv, family arenaviridae, genus arenavirus, which is maintained in its natural rodent reservoir, the multimammate rat mastomys natalensis.
Lassa fever is endemic in parts of west africa, to include the following areas. Sensitivity and specificity of diagnostic tests for lassa fever. The centers for disease control and prevention estimates that up to 300,000 lassa virus infections occur each year. Lassa virus is a member of the old world arenaviruses, and, as such, is endemic in western africa. We sequenced lasv rna genome from positive cases of lf between 2012 and 2016 which were reported at. Lassa fever is common in west africa and can cause similar symptoms as ebola. We used reverse transcription pcr and resequencing microarrays. Lassa fever lf is a severe and often fatal hemorrhagic disease caused by lassa virus lasv, a member of the arenaviridae virus family.
When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria. For 40 years, the natal multimammate rat, mastomys natalensis, has been assumed to be the sole host of lasv. There are four lassa virus lineages with significant genetic diversity 8, 9, although it has been proposed that a fifth lineage could be defined by subdividing lineage iv. 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. Author summary lassa fever lf is a viral hemorrhagic fever caused by lassa virus lasv. Of 10 specimens captured in kako, southwestern nigeria, during this period, 4 were lasv positive table 1. The lassa virus, endemic to west africa, uses an unexpected twostep process to enter cells, research has shown. When a person who may have lassa fever seeks medical attention, proper transmission prevention measures must be taken.
Lassa virus is endemic to west africa and causes hemorrhagic fever in humans. Partial gp sequences of these strains, labeled nig09ospmh86, 89, 123. Heal the world mikaela gordon, morley dupuy, and jirom yibrah treatment the easiest way to test for the lassa virus would be to isolate it from the blood, urine, or throat washings. Ribavirin has been used with success in lassa fever patients. Lassa fever is an acute viral haemorrhagic illness caused by lassa virus, a member of. Lassa fever is an acute viral infection associated with a wide spectrum of disease manifestations, which range from mild to hemorrhagic fever characterized by multiorgan failure. Lassa fever death rates in nigeria higher than expected cnn. Viruses were propagated in cell culture under biosafety level bsl4 or bsl3 conditions. May 03, 2016 lassa virus lasv causes a deadly haemorrhagic fever in humans, killing several thousand people in west africa annually.
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