Prevalence, pathogenesis, and persistence of lassa fever. The arenavirus lassa causes a severe illness called lassa fever lassa fever was first recognized following the deaths of two nurses in nigeria in 1969. This process is experimental and the keywords may be updated as the learning algorithm improves. Lassa virus lasv infection causes an acute and sometimes fatal hemorrhagic disease in humans and nonhuman primates. A potent lassa virus antiviral targets an arenavirus. Observed casefatality rate among patients hospitalized with severe cases of lassa fever is 15%. This experience will be applied to the study of lassa fever. Infection with lassa virus in humans may take many forms.
Lassa fever is known to be endemic in guinea, liberia, sierra leone and parts of nigeria, but probably exists in other west african countries as well. The reservoir of the lassa virus is a rodent of the genus mastomys known as multimammate rat. 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. Here, we performed a pilot study to begin to understand the progression of lasv infection in nonhuman primates. Treatment of infected patients since the initial observation in 1969 of the disease has been largely symptomatic and supportive.
To allow study of infection by lasv under bsl2 conditions, we generated a recombinant virus in which the lasv glycoprotein gp was placed on the backbone of lymphocytic choriomeningitis virus lcmv cl nucleoprotein, z and polymerase genes rlcmv cllasv gp. May 26, 2015 amorosa v, macneil a, mcconnell r, et al. Originally found in nigeria, outbreaks have been reported from sierra leone, liberia, and guinea. Hemorrhagic disease lassa fever lassa virus argentine haemorrhagic fever immune plasma these keywords were added by machine and not by the authors. New opportunities for field research on the pathogenesis and treatment of lassa fever.
Lassa mammarenavirus lasv is an arenavirus that causes lassa hemorrhagic fever, a type of viral hemorrhagic fever vhf, in humans and other primates. The animal reservoir is the rodent multimammate rat mastomys natalensis. Collectively, the proposed work will provide a muchneeded characterization of lassa fever epidemiology, pathogenesis, and compartmental viral dynamics and will provide a wellspring of data that will inform public policy and individual care. The incubation period of lassa fever ranges from 7 to 21 days 34, 58. A rodent model for human lassa fever was developed which uses inbred strain and outbred hartley guinea pigs. We have been publishing the results of basic research in all branches of virology for over 60 years. The symptoms of lassa fever can be nonspecific and mimic those of other endemic infections, especially early in illness, making a clinical diagnosis difficult. Pathogenesis of lassa fever in cynomolgus macaques lisa e hensley1, mark a smith2, joan b geisbert3,4, elizabeth a fritz3,4, kathleen m daddariodicaprio1, tom larsen2 and thomas w geisbert3,4 abstract background. Prevalence, pathogenesis, and persistence of lassa fever in.
Full text current research for a vaccine against lassa. Lassa fever may be transmitted from either infected animals typically rodents or humans following exposure to body fluids and excretionssecretions from the respiratory tract or gi tract. New opportunities for field research on the pathogenesis. Baseline mapping of lassa fever virology, epidemiology and. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria. Viruses free fulltext pathogenesis of lassa fever html. The incubation period of lassa fever ranges from 7 to 21 days 34,58. 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 mammarenavirus is an emerging virus and a select agent, requiring biosafety level 4equivalent containment. Pathology and pathogenesis of arenavirus infections. Lassa virus infection occurs through contact with the vector mastomys natalensis or infected humans and can lead to wide symptoms from a mild. Structure of the lassa virus nucleoprotein reveals a dsrna.
Lassa virus was isolated from rodents of the genus mastomys, members of which aggressively invade houses. 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. In spite of ongoing research efforts, lf pathogenesis and mechanisms of lasv immune control remain poorly understood. Laboratory diagnosis of lassa fever journal of clinical. Lassa virus lasv infection causes an acute and sometimes fatal hemorrhagic disease in humans and. Many of those infected by the virus do not develop symptoms. Clinical description and pathogenesis of lassa fever.
The onset of the disease, when it is symptomatic, is usually gradual, starting with fever, general weakness, and malaise. Lassa fever is one of the hemorrhagic fever viruses, occurring in west africa subregions in similar areas as ebola virus. Lassa fever was first recognized in lassa, nigeria, in 1969 and is endemic to west africa. 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. The commonality of pathologic and histopathologic findings in cases of fatal arenavirus hemorrhagic fever suggests some common pathogenic mechanisms, but the differences reinforce the need for comprehensive study of each disease in naturally infected humans and in experimental animal models that mimic human infections. Research open access pathogenesis of lassa fever in. 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. The incubation period of lassa fever ranges from 621 days. The journal welcomes submitted articles on virus replication, virushost biology, viral pathogenesis, immunity to viruses, virus structure, and virus evolution and ecology.
Spectrum of clinical effects manifested in lassa fever range from asymptomatic to multiorgan system failure and death. For hepatitis c, it is used in combination with other medications such as simeprevir, sofosbuvir, peginterferon alfa2b or peginterferon alfa2a. The case fatality rate was 25% among confirmed cases, underscoring the need for an effective antiviral therapy. In contrast, lassa fever lf virus, an arenavirus, is resistant to interferon, and lf is terminated by cellular immune effector mechanisms. 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. Antiviral research 78 2008 103115 new opportunities for. Ribavirin, also known as tribavirin, is an antiviral medication used to treat rsv infection, hepatitis c and some viral hemorrhagic fevers. Jul 31, 2017 lassa fever is known to be endemic in benin, ghana, guinea, liberia, mali, sierra leone, and nigeria, but probably exists in other west african countries as well. The virus is endemic in west african countries, which may be due to its zoonotic nature. Pathogenesis of lassa fever in cynomolgus macaques. 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. Pathophysiology and treatment of lassa fever springerlink. The pathology of human lassa fever pathophysiology and treatment of lassa fever effective vaccine for lassa fever. Here we propose a concept whereby the bodys immune defense either defeats lasv rapidly or, if unsuccessful, becomes an essential facilitator of disease.
The clinical disease begins as a flulike illness characterized by fever, general weakness, and malaise, which may be accompanied by. The onset of the disease, when it is symptomatic, is usually gradual, starting with fever, general weakness, and. O human infection with lassa virus is a severe, gen data have suggested that mild or subclinical infeceralized disease described as lassa fever 1. Molecular diagnostics for lassa fever at irrua specialist teaching hospital, nigeria. Clinical description and pathogenesis of lassa fever the incubation period of lassa fever ranges from 7 to 21 days 34,58. Clinical description and pathogenesis of lassa fever the incubation period of lassa fever ranges from 7 to 21 days 34, 58. Pathogenesis of lassa fever in cynomolgus macaques springer. Oct 05, 2015 lassa fever is endemic to west africa. Yet the mechanisms leading to disease remain poorly understood.
Virology publishes papers that provide advances to the understanding of virus biology. Pathogenesis of lassa virus infection in guinea pigs. Viral hemorrhagic fevers vhfs are a group of febrile illnesses caused by rna viruses from several viral families. Lassa fever flavivirus dengue, hepatitis c, yellow fever retroviruses hiv1, hiv2, htlv needs to be covered in greater detail than other viruses tropism for lymphocytes, macrophages, and effects on the immune system. Articles should be of broad interest to the community of virologists.
These highly infectious viruses lead to a potentially lethal disease syndrome characterized by fever, malaise, vomiting, mucosal and gastrointestinal gi. The disease is endemic in west africa, and an unusually large outbreak occurred in nigeria in early 2018. Lassa fever disease lassa fever is viral illness that occurs in west africa. Pathogenesis of lassa fever utmb health research expert. Six cynomolgus monkeys were experimentally infected with lasv. When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. N2 lassa virus, an old world arenavirus family arenaviridae, is the etiological agent of lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic regions of west africa with mortality rates for hospitalized patients varying. Lassa virus lasv, the causative agent of lassa fever lf, is endemic in west africa, accounting for substantial morbidity and mortality. Lassa virus, an old world arenavirus family arenaviridae, is the etiological agent of lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic regions of west africa with mortality rates for hospitalized patients varying between 510%. Currently, there are no approved vaccines against lassa fever for use in humans. Lassa fever is a hemorrhagic illness caused by lassa virus. Pdf pathogenesis of lassa fever in cynomolgus macaques. Jan 05, 2020 the incubation period of lassa fever ranges from 621 days.
Research open access pathogenesis of lassa fever in cynomolgus macaques lisa e hensley1, mark a smith2, joan b geisbert3,4, elizabeth a fritz3,4, kathleen m daddariodicaprio1, tom larsen2 and thomas w geisbert3,4 abstract background. Lassa virus is one of more than 25 causative viruses of viral hemorrhagic fever table 4. 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. Here, we performed a pilot study to begin to understand the progression of. Pathogenesis of lassa fever in cynomolgus macaques virology. Among the viral hemorrhagic fevers it is used for lassa fever, crimeancongo hemorrhagic fever, and. Lassa virus, an old world arenavirus family arenaviridae, is the etiological agent of lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic regions of west africa with mortality rates for hospitalized. 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. Infection with rift valley fever rvf virus, a phlebovirus, appears to be regulated by interferon and terminated by neutralizing antibody. The clinical disease begins as a flulike illness characterized by fever, general weakness, and malaise, which may be accompanied by cough, sore throat, and severe headache. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. Lassa virus is a linear, bisegmented, singlestranded rna virus, which belong to the arenaviridae family that causes viral hemorrhagic fever transmitted by rats. Lassa virus, an old world arenavirus family arenaviridae, is the etiological agent of lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic.
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