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Pathogenic Old World arenaviruses inhibit TLR2/Mal-dependent proinflammatory cytokines in vitro.

Lymphocytic choriomeningitis virus (LCMV), the prototype arenavirus, and Lassa virus (LASV), the causative agent of Lassa fever (LF), have extensive strain diversity and significant variations in pathogenicity for humans and experimental animals. The WE strain of LCMV (LCMV-WE), but not the Armstrong (Arm) strain, induces a fatal LF-like disease in rhesus macaques. We also demonstrated that LASV infection of human macrophages and endothelial cells resulted in reduced levels of proinflammatory cytokines. Here we have shown that cells infected with LASV or with LCMV-WE suppressed Toll-like recep…

A Sporadic and Lethal Lassa Fever Case in Forest Guinea, 2019.

Lassa fever is a rodent-borne disease caused by Lassa virus (LASV). It causes fever, dizziness, vertigo, fatigue, coughing, diarrhea, internal bleeding and facial edema. The disease has been known in Guinea since 1960 but only anectodical acute cases have been reported to date. In January 2019, a 35-year-old man, a wood merchant from Kissidougou, Forest Guinea, presented himself at several health centers with persistent fever, frequent vomiting and joint pain. He was repeatedly treated for severe malaria, and died three weeks later in Mamou regional hospital. Differential diagnosis identified …

Evaluation of candidate reference materials for the harmonization of Lassa fever serology.

Lassa fever is a zoonotic disease endemic to several West African countries, with seasonal outbreaks and potential to cause future epidemics. Vaccines and other medical countermeasures are in development, requiring reliable assays for evaluation. A WHO International Standard (IS) for anti-Lassa virus (LASV) antibodies can support harmonization of serological assay results, aiding vaccine and therapeutic assessment, surrogates of protection identification, and improving epidemiological understanding. In this study, a pooled plasma sample from Lassa fever survivors was evaluated in a multi-centr…

A regional coalition for Lassa fever vaccine development and preparedness in West Africa: A practice-based perspective.

BACKGROUND: Lassa fever causes an estimated 100,000-300,000 infections annually in West Africa, yet vaccine development and country preparedness efforts have remained fragmented. In response, the Lassa Fever Vaccine Coalition (LFVC) was established in 2024 by the Coalition for Epidemic Preparedness Innovations (CEPI) and the West African Health Organization (WAHO) to align research, policy, and readiness across endemic countries. METHODS: This practice-based Perspective draws on the authors' experiences as coalition secretariat and founding partners, supplemented by internal program documents

Electroencephalography in emerging viral infections: Lessons learned from implementing an EEG unit in a Lassa fever isolation ward in Nigeria.

Electroencephalography (EEG) has been used for almost a century in well-equipped medical centers to facilitate the diagnosis of epilepsy and other brain disorders. Lassa fever (LF) and other emerging viral infections (EVI) are known to cause neurological complications, including meningitis, seizures, and encephalopathy, though to date it remains unclear whether these are secondary to metabolic disturbances caused by the disease or by direct involvement of the central nervous system (CNS). To better characterize how Lassa virus (LASV) affects the CNS, we established an EEG diagnostic unit in th…

Meeting report: WHO consultation on accelerating Lassa fever vaccine development in endemic countries, Dakar, 10-11 September 2019.

At the time of writing in 2019, there have been 754 confirmed cases of Lassa fever in Nigeria, 21% of whom have died. Lassa is on the priority pathogen list for WHO's R&D Blueprint for Action to Prevent Epidemics. In September 2019, WHO convened 67 scientists, regulators, ethicists, public health officials, funders and vaccine developers to discuss the end-to-end clinical development plan for Lassa fever vaccines. The substantial increases in vaccine trial capacity in Africa were reviewed, together with lessons learned from the evaluation of vaccines against HIV, TB, malaria, and Ebola in Afri

Обстановка на каучуковых плантациях и эпидемии лихорадки Ласса в Либерии, 2008-2012 годы: пространственная регрессия.

Поскольку лихорадка Ласса по-прежнему является одной из проблем здравоохранения в Западной Африке, крайне важно составить хорошие карты ее рисков для использования в рамках активного наблюдения и контроля. Мы выявили восемь пространственных особенностей, связанных с окружающей средой каучуковых плантаций, и использовали их в качестве пояснительных переменных для вспышек лихорадки Ласса (ЛЛЛ) на каучуковых плантациях Uniroyal Liliberian Agricultural Company (LAC) в графстве Гранд-Басса, Либерия. Мы рассчитали классические и пространственные регрессионные модели на всех пространственных особенно

Совпадение в аннотации оригинала
As Lassa fever continues to be a public health challenge in West Africa, it is critical to produce good maps of its risk pattern for use in … ed that the rubber plantation environment influenced Mastomys species' breeding and transmission of Lassa virus along spatial scale to humans. The risk factors identified in this study offered a baseline for more effective surveillance and control of LF in the post-civil conflict Liberia.

Risk maps of Lassa fever in West Africa.

BACKGROUND: Lassa fever is caused by a viral haemorrhagic arenavirus that affects two to three million people in West Africa, causing a mortality of between 5,000 and 10,000 each year. The natural reservoir of Lassa virus is the multi-mammate rat Mastomys natalensis, which lives in houses and surrounding fields. With the aim of gaining more information to control this disease, we here carry out a spatial analysis of Lassa fever data from human cases and infected rodent hosts covering the period 1965-2007. Information on contemporary environmental conditions (temperature, rainfall, vegetation) …

A DNA vaccine delivered by dermal electroporation fully protects cynomolgus macaques against Lassa fever.

Lassa virus (LASV) is an ambisense RNA virus in the Arenaviridae family and is the etiological agent of Lassa fever, a severe hemorrhagic disease endemic to West and Central Africa. 1,2 There are no US Food and Drug Administration (FDA)-licensed vaccines available to prevent Lassa fever. 1,2 in our previous studies, we developed a gene-optimized DNA vaccine that encodes the glycoprotein precursor gene of LASV (Josiah strain) and demonstrated that 3 vaccinations accompanied by dermal electroporation protected guinea pigs from LASV-associated illness and death. Here, we describe an initial effic…

[Viral haemorrhagic fevers--evolution of the epidemic potential].

In this review modern data on dangerous and particularly dangerous viral haemorrhagic fevers caused by a group of viruses belonging to the families of phylo-, arena-, flavi-, bunya- and togaviruses are presented. Morbidity rates and epidemics caused by Marburg virus, Ebola fever virus, Lassa fever virus, Argentinian and Bolivian haemorrhagic fever viruses, dengue haemorrhagic fever virus, Crimean haemorrhagic fever virus, Hantaviruses are analyzed. Mechanisms of the evolution of the epidemic manifestation of these infections are considered. The importance of the development of tools and method

Lassa fever and Argentine hemorrhagic fever treatment in guinea pigs using broad-spectrum cap-dependent endonuclease inhibitors.

The class Bunyaviricetes encompasses several highly pathogenic viruses that cause lethal hemorrhagic fevers. Due to their limited prevention … viruses for which no approved antiviral treatments currently exist.IMPORTANCEArenaviruses, such as Lassa virus and Junin virus, cause severe hemorrhagic fevers in humans and are associated with high mortality rates and limited treatment options. Because of their pathogenicity and potential for outbreaks, these viruses represent an important global health thr …

The search for animal models for Lassa fever vaccine development.

Lassa virus (LASV) is the most prevalent arenavirus in West Africa and is responsible for several hundred thousand infections and thousands of deaths annually. The sizeable disease burden, numerous imported cases of Lassa fever (LF) and the possibility that LASV can be used as an agent of biological warfare make a strong case for vaccine development. Currently there is no licensed LF vaccine and research and devlopment is hampered by the high cost of nonhuman primate animal models and by biocontainment requirements (BSL-4). In addition, a successful LF vaccine has to induce a strong cell-media…

Exotic viral diseases.

Marburg virus disease, Lassa fever, monkeypox, and Ebola virus diseases of humans have all been recognized since 1967. These are examples of some of the exotic virus diseases which through importation may present a potential public health problem in the United States. Some of these viruses are also highly hazardous to laboratory and medical personnel. This paper is a review of the general characteristics, the epidemiology, and laboratory diagnosis of the exotic viruses which have been described during the last 25 years.

[Highly contagious diseases with human-to-human transmission].

Highly contagious diseases are caused by various biological agents that pose a risk to individuals and may have a potential for public health impact. They result in high mortality and morbidity rates, might cause public panic and therefore require special measures. The pathogens that can be easily disseminated or transmitted from person to person are the riskiest for clinicians (Ebola virus, Marburg virus, Lassa virus, Crimean-Congo hemorrhagic fever virus, Variola major, SARS virus and Yersinia pestis). Human-to-human transmission has not been confirmed for the other biological agents and the…

Lassa fever cases and mortality in Nigeria: Quantile Regression vs. Machine Learning Models.

Lassa fever (LF) is caused by the Lassa fever virus (LFV). It is endemic in West Africa, of which % of the infections are ascribed to Nigeria. This disease affects mostly the productive age and hence a proper understanding of the dynamics of this disease will help in formulating policies that would help in curbing the spread of LF. The objective of this study is to compare the performance of quantile regression models with that of Machine Learning models in. Data between between 7th January 2018 2018 and 17th December, 2022 on suspected cases, confirmed cases and deaths resulting from LF were

The pathology of human Lassa fever.

Pathological findings have been described in only a small number of cases of Lassa fever since the virus was first isolated in 1969. Morphologically, eosinophilic necrosis of hepatocytes was the most frequent finding and focal necroses, often extensive, were present in most cases. These findings are similar to the lesions previously described in Argentinian and Bolivian haemorrhagic fever. Focal interstitial pneumonitis, focal tubular necrosis in the kidney, lymphocytic infiltration of the splenic veins, and partial replacement of the splenic follicles by amorphous eosinophilic material have b

The ecology of Praomys (Mastomys) natalensis in southern Africa.

The only non-human host of Lassa virus so far identified is the multimammate mouse, Praomys (Mastomys) natalensis, but its precise role in the natural Lassa fever cycle remains to be determined. This species is also an important link in the plague cycle in southern Africa and is one of the commonest rodents of Africa. It is a prolific breeder and can be kept and bred easily in captivity. It is thus an excellent laboratory animal, although it needs to be handled with care because it is aggressive towards man and bites readily. The current status of knowledge of its taxonomy, ecology, distributi…

O'nyong'nyong Virus Infections in Nigeria: A Case Series.

We report seven patients with detected o'nyong'nong virus infection, presenting with acute febrile illness at two tertiary hospitals in Nigeria. The clinical presentation mimicked malaria and Lassa fever, highlighting the need for expanded arboviral surveillance and diagnostics to distinguish emerging viral infections in endemic settings.

Challenges Associated With Re-Emergence of Lassa Fever in Nigeria: An Exploratory Study of Epidemiology, Phylogenomics, and Recommendations Toward Its Eradication.

BACKGROUND: Lassa fever (LF) is a viral hemorrhagic illness endemic in Nigeria and other West African countries. In recent years, the number of reported cases of LF in Nigeria has increased. In this study, we discussed the epidemiology of LF, the phylogenomics of the LF virus, issues associated with the increased cases of LF, and recommendations for tackling the future occurrence of LF in Nigeria. METHODS: Epidemiology data on LF were obtained from the Nigeria Centre for Disease Control database and analyzed using Microsoft Excel software. About 59 partial and complete sequences consisting of