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Molecular pathogenesis of viral hemorrhagic fever.

The clinical syndrome referred to as viral hemorrhagic fever (VHF) can be caused by several different families of RNA viruses, including sel … fic molecular pathways that underlie these features of VHF remain poorly understood. The arenavirus Lassa virus and the flavivirus yellow fever virus exhibit similar molecular pathogenesis suggesting common underlying mechanisms. Because non-human primate models that closely mimic VHF are available for Ebola, Lassa, and yellow fever viruses, we propose that c …

Physiological and immunologic disturbances associated with shock in a primate model of Lassa fever.

The degree of cell and organ damage in clinical and histological studies of patients dying of Lassa fever has been insufficient to explain the catastrophic shock characteristic of the fatal illness. To explore this issue further, we conducted a study of the evolution of shock in three Lassa virus-infected rhesus monkeys. By the sixth day after infection, a marked, progressive reduction of in vitro platelet aggregation occurred despite normal numbers of circulating platelets and a normal platelet survival time and was accompanied by loss of prostacyclin production by postmortem endothelium. Bot…

Detection of hepatitis viruses in suspected cases of Viral Haemorrhagic Fevers in Nigeria.

There have been several Viral Hemorrhagic Fever (VHF) outbreaks in Nigeria which remains a public health concern. Despite the increasing number of suspected cases of VHF due to heightened surveillance activities and growing awareness, only a few cases are laboratory-confirmed to be VHF. Routinely, these samples are only tested for Lassa virus and Yellow fever virus with occasional testing for Dengue virus when indicated. The aetiology of the disease in these VHF suspected cases in Nigeria which are negative for Lassa, Yellow fever and Dengue viruses remains a puzzle. Since the clinical feature…

Effective oral favipiravir (T-705) therapy initiated after the onset of clinical disease in a model of arenavirus hemorrhagic Fever.

BACKGROUND: Lassa and Junín viruses are the most prominent members of the Arenaviridae family of viruses that cause viral hemorrhagic fever syndromes Lassa fever and Argentine hemorrhagic fever, respectively. At present, ribavirin is the only antiviral drug indicated for use in treatment of these diseases, but because of its limited efficacy in advanced cases of disease and its toxicity, safer and more effective antivirals are needed. METHODOLOGY/PRINCIPAL FINDINGS: Here, we used a model of acute arenaviral infection in outbred guinea pigs based on challenge with an adapted strain of Pichindé

Lassa fever. Effective therapy with ribavirin.

In a study of Lassa fever in Sierra Leone, West Africa, we identified two variables associated with a high risk of death, and we evaluated the efficacy of ribavirin and Lassa virus-convalescent plasma for the treatment of Lassa fever. A serum aspartate aminotransferase level greater than or equal to 150 IU per liter at the time of hospital admission was associated with a case-fatality rate of 55 percent (33 of 60). Patients with the same risk factor who were treated for 10 days with intravenous ribavirin, begun within the first 6 days after the onset of fever, had a case-fatality rate of 5 per…

Potent immunogenicity and protective efficacy of a multi-pathogen vaccination targeting Ebola, Sudan, Marburg and Lassa viruse.

Viral haemorrhagic fevers (VHF) pose a significant threat to human health. In recent years, VHF outbreaks caused by Ebola, Marburg and Lassa viruses have caused substantial morbidity and mortality in West and Central Africa. In 2022, an Ebola disease outbreak in Uganda caused by Sudan virus resulted in 164 cases with 55 deaths. In 2023, a Marburg disease outbreak was confirmed in Equatorial Guinea and Tanzania resulting in over 49 confirmed or suspected cases; 41 of which were fatal. There are no clearly defined correlates of protection against these VHF, impeding targeted vaccine development.…

Clinical features and patient management of Lujo hemorrhagic fever.

BACKGROUND: In 2008 a nosocomial outbreak of five cases of viral hemorrhagic fever due to a novel arenavirus, Lujo virus, occurred in Johannesburg, South Africa. Lujo virus is only the second pathogenic arenavirus, after Lassa virus, to be recognized in Africa and the first in over 40 years. Because of the remote, resource-poor, and often politically unstable regions where Lassa fever and other viral hemorrhagic fevers typically occur, there have been few opportunities to undertake in-depth study of their clinical manifestations, transmission dynamics, pathogenesis, or response to treatment op…

Hiding the evidence: two strategies for innate immune evasion by hemorrhagic fever viruses.

The innate immune system is one of the first lines of defense against invading pathogens. Pathogens have, in turn, evolved different strategies to counteract these responses. Recent studies have illuminated how the hemorrhagic fever viruses Ebola and Lassa fever prevent host sensing of double-stranded RNA (dsRNA), a key hallmark of viral infection. The ebolavirus protein VP35 adopts a unique bimodal configuration to mask key cellular recognition sites on dsRNA. Conversely, the Lassa fever virus nucleoprotein actually digests the dsRNA signature. Collectively, these structural and functional st

Exchange transfusion of a patient with fulminant Lassa fever.

We report a patient with fulminant Lassa fever who responded dramatically to a 2.5-litre exchange transfusion of whole blood. On admission h … further evaluation of this therapeutic approach is justified in selected patients with overwhelming Lassa virus infection.

An orally available 4'-fluorouridine prodrug inhibits SFTSV and LCMV infection.

Bunyaviruses, a subset of segmented negative-sense RNA viruses, include pathogenic species capable of zoonotic transmission to humans via ar … pathogens (including severe acute respiratory syndrome coronavirus 2, respiratory syncytial virus, Lassa virus, and Junin virus), VV251 emerges as a promising next-generation oral antiviral candidate, offering an orally available therapeutic option to combat these formidable pathogens.

[Recent Lassa, Marbourg and Ebola viruses in African tropical viruses. I. Semiology--physiopathology--diagnosis--treatment (author's transl)].

Three new viruses have been identified in Africa during the present decade. They may cause sporadic cases or limited outbreaks, and they are probably endemic in areas which are still ill-defined. Severe forms of infection lead to the haemorrhagic syndrome or to hypovolemic shock, the physiopathology of which is being studied. The case-fatality ratio of severe cases is between 30 and 85 per cent. Nosocomial outbreaks have been observed, but they can be avoided if appropriate barrier nursing measures are carried out for the treatment of patients or adequate protection measures for sampling and e

Contact Networks of Small Mammals Highlight Potential Transmission Foci of Mammarenavirus lassaense.

Lassa fever (LASV; Mammarenavirus lassaense) is an endemic zoonosis in West Africa. Human infections arise from rodent-to-human transmission, primarily from the synanthropic reservoir Mastomys natalensis (M. natalensis). In Sierra Leone, small-mammal communities vary across land-use gradients, shaping LASV transmission risk. How anthropogenic environments facilitate the rodent-rodent interactions remains poorly understood. Small mammals were sampled over 43,266 trap nights in Sierra Leone's LASV-endemic Eastern Province, detecting 684 rodents and shrews. To assess potential transmission, space

Epidemiological analysis of Lassa fever control using novel mathematical modeling and a dual-dosage vaccination approach.

Lassa fever is a serious health issue in West Africa that requires deeper understanding in order to be effectively controlled. Compared to conventional integer-order methods, this study presents an improved analysis of disease dynamics, including vaccine efficacy, by utilizing fractional-order models and the Laplace Adomian Decomposition methods. This research highlights the critical role of fractional-order dynamics and vaccination impact in understanding Lassa fever transmission and evaluating control strategies. It employs stability and sensitivity analyses, as well as the next-generation m

Ecological correlates and predictors of Lassa fever incidence in Ondo State, Nigeria 2017-2021: an emerging urban trend.

Lassa fever (LF) is prevalent in many West African countries, including Nigeria. Efforts to combat LF have primarily focused on rural areas where interactions between rodents and humans are common. However, recent studies indicate a shift in its occurrence from rural to urban areas. We analysed secondary data of reported LF outbreaks from 2017 to 2021 in Ondo State, Nigeria to identify the distribution pattern, ecological variations, and other determinants of disease spread from the ward level using nearest neighbour statistics and regression analysis. Data utilised include LF incidence, ecolo

Lassa fever vaccine.

Lassa fever remains a serious challenge to public health in West Africa threatening both local residents in rural areas and those who serve … ives have suffered from a lack of funding in the past but bioterrorism has brought new resources to Lassa virus science. Adequate funding and applications of new vaccine technologies give hope that we may soon see a vaccine in clinical trials. However, the difficulty of conducting trials in endemic areas and lack of political stability remain serious problems …

Scalable Bayesian Divergence Time Estimation With Ratio Transformations.

Divergence time estimation is crucial to provide temporal signals for dating biologically important events from species divergence to viral … ian framework to learn the divergence times in 4 pathogenic viruses (West Nile virus, rabies virus, Lassa virus, and Ebola virus) and the coralline red algae. Our method both resolves a mixing issue in the West Nile virus example and improves inference efficiency by at least 5-fold for the Lassa and rabies virus examples as well as for the algae example. Our …

Ниша " Одно здоровье " подходит к наблюдению за лихорадкой Ласса и борьбе с ней.

В западноафриканских странах, где вирус Ласса (LASV) циркулирует среди грызунов, лихорадка Ласса (LF) является зоонотической болезнью. Воздействие на человека в значительной степени зависит от экологии ЛАГВ, которая в свою очередь определяется различными параметрами, такими, как сезонность погоды и даже генетика вируса и грызунов. Кроме того, поведение человека, несмотря на то, что оно играет ключевую роль в зоонотической природе болезни, оказывает серьезное воздействие либо на распространение, либо на контроль над передачей заболевания от человека к человеку. Предыдущие оценки нагрузки на ЛФ

Совпадение в аннотации оригинала
Lassa fever (LF), a zoonotic illness, represents a public health burden in West African countries where the Lassa virus (LASV) circulates among rodents. Human exposure hinges significantly on LASV ecology, which is in turn shaped by various parameters such as weather seasonality and even virus and rodent-host genetics. Furthermore, human behaviour, despite p…