scholarly journals Deployable CRISPR-Cas13a diagnostic tools to detect and report Ebola and Lassa virus cases in real-time

2020 ◽  
Author(s):  
Kayla G. Barnes ◽  
Anna E. Lachenauer ◽  
Adam Nitido ◽  
Sameed Siddiqui ◽  
Robin Gross ◽  
...  
Keyword(s):  
Ebola Virus ◽  
Virus Disease ◽  
Lassa Fever ◽  
Diagnostic Tools ◽  
Clinical Samples ◽  
Viral Diversity ◽  
Lassa Virus ◽  
Live Attenuated Vaccine ◽  
Safety Testing ◽  
User Friendly

AbstractViral hemorrhagic fevers (VHFs) remain some of the most devastating human diseases, and recent outbreaks of Ebola virus disease (EVD) 1,2 and Lassa fever (LF) 3,4 highlight the urgent need for sensitive, field-deployable tests to diagnose them 5,6. Here we develop CRISPR-Cas13a-based (SHERLOCK) diagnostics targeting Ebola virus (EBOV) and Lassa virus (LASV), with both fluorescent and lateral flow readouts. We demonstrate on laboratory and clinical samples the sensitivity of these assays and the capacity of the SHERLOCK platform to handle virus-specific diagnostic challenges. Our EBOV diagnostic detects both the L and NP genes, thereby eliminating the potential for false positive results caused by the rVSVΔG-ZEBOV-GP live attenuated vaccine. Our two LASV diagnostics together capture 90% of known viral diversity and demonstrate that CRISPR-RNAs (crRNAs) can be effectively multiplexed to provide greater coverage of known viral diversity. We performed safety testing to demonstrate the efficacy of our HUDSON protocol in heat-inactivating and chemically treating VHF viruses before SHERLOCK testing, eliminating the need for an extraction. We developed a user-friendly field protocol and mobile application (HandLens) to report results, facilitating SHERLOCK’s use in endemic regions. Finally, we successfully deployed our tests in Sierra Leone and Nigeria in response to recent outbreaks.

Serosurvey on healthcare personnel caring for patients with Ebola virus disease and Lassa virus in the United States

2020 ◽  
Vol 41 (4) ◽  
pp. 385-390
Author(s):  
Colleen S. Kraft ◽  
Aneesh K. Mehta ◽  
Jay B. Varkey ◽  
G. Marshall Lyon ◽  
Sharon Vanairsdale ◽  
...  
Keyword(s):  
Infection Control ◽  
Ebola Virus ◽  
Virus Disease ◽  
Adenovirus Type ◽  
The United States ◽  
Ebola Virus Disease ◽  
University Hospital ◽  
Healthcare Personnel ◽  
Lassa Virus ◽  
Serum Samples

AbstractObjective:Healthcare personnel (HCP) were recruited to provide serum samples, which were tested for antibodies against Ebola or Lassa virus to evaluate for asymptomatic seroconversion.Setting:From 2014 to 2016, 4 patients with Ebola virus disease (EVD) and 1 patient with Lassa fever (LF) were treated in the Serious Communicable Diseases Unit (SCDU) at Emory University Hospital. Strict infection control and clinical biosafety practices were implemented to prevent nosocomial transmission of EVD or LF to HCP.Participants:All personnel who entered the SCDU who were required to measure their temperatures and complete a symptom questionnaire twice daily were eligible.Results:No employee developed symptomatic EVD or LF. EVD and LF antibody studies were performed on sera samples from 42 HCP. The 6 participants who had received investigational vaccination with a chimpanzee adenovirus type 3 vectored Ebola glycoprotein vaccine had high antibody titers to Ebola glycoprotein, but none had a response to Ebola nucleoprotein or VP40, or a response to LF antigens.Conclusions:Patients infected with filoviruses and arenaviruses can be managed successfully without causing occupation-related symptomatic or asymptomatic infections. Meticulous attention to infection control and clinical biosafety practices by highly motivated, trained staff is critical to the safe care of patients with an infection from a special pathogen.

scholarly journals The Case for Improved Diagnostic Tools to Control Ebola Virus Disease in West Africa and How to Get There

2015 ◽  
Vol 9 (6) ◽  
pp. e0003734 ◽  
Author(s):  
Arlene C. Chua ◽  
Jane Cunningham ◽  
Francis Moussy ◽  
Mark D. Perkins ◽  
Pierre Formenty
Keyword(s):  
West Africa ◽  
Ebola Virus ◽  
Virus Disease ◽  
Ebola Virus Disease ◽  
Diagnostic Tools

scholarly journals An Outbreak of Ebola Virus Disease in the Lassa Fever Zone

2016 ◽  
Vol 214 (suppl 3) ◽  
pp. S110-S121 ◽  
Author(s):  
Augustine Goba ◽  
S. Humarr Khan ◽  
Mbalu Fonnie ◽  
Mohamed Fullah ◽  
Alex Moigboi ◽  
...  
Keyword(s):  
Ebola Virus ◽  
Virus Disease ◽  
Lassa Fever ◽  
Ebola Virus Disease

scholarly journals Lassa viral dynamics in non-human primates treated with favipiravir or ribavirin

2021 ◽  
Vol 17 (1) ◽  
pp. e1008535
Author(s):  
Guillaume Lingas ◽  
Kyle Rosenke ◽  
David Safronetz ◽  
Jérémie Guedj
Keyword(s):  
Mechanism Of Action ◽  
Ebola Virus ◽  
Antiviral Treatment ◽  
Antiviral Effect ◽  
Lassa Fever ◽  
Pharmacokinetic Data ◽  
Virus Infectivity ◽  
Lassa Virus ◽  
Viral Dynamics

Lassa fever is an haemorrhagic fever caused by Lassa virus (LASV). There is no vaccine approved against LASV and the only recommended antiviral treatment relies on ribavirin, despite limited evidence of efficacy. Recently, the nucleotide analogue favipiravir showed a high antiviral efficacy, with 100% survival obtained in an otherwise fully lethal non-human primate (NHP) model of Lassa fever. However the mechanism of action of the drug is not known and the absence of pharmacokinetic data limits the translation of these results to the human setting. Here we aimed to better understand the antiviral effect of favipiravir by developping the first mathematical model recapitulating Lassa viral dynamics and treatment. We analyzed the viral dynamics in 24 NHPs left untreated or treated with ribavirin or favipiravir, and we put the results in perspective with those obtained with the same drugs in the context of Ebola infection. Our model estimates favipiravir EC50 in vivo to 2.89 μg.mL-1, which is much lower than what was found against Ebola virus. The main mechanism of action of favipiravir was to decrease virus infectivity, with an efficacy of 91% at the highest dose. Based on our knowledge acquired on the drug pharmacokinetics in humans, our model predicts that favipiravir doses larger than 1200 mg twice a day should have the capability to strongly reduce the production infectious virus and provide a milestone towards a future use in humans.

scholarly journals A Lassa Virus Live-Attenuated Vaccine Candidate Based on Rearrangement of the Intergenic Region

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Yingyun Cai ◽  
Masaharu Iwasaki ◽  
Daisuke Motooka ◽  
David X. Liu ◽  
Shuiqing Yu ◽  
...  
Keyword(s):  
Intergenic Region ◽  
Guinea Pigs ◽  
Cultured Cells ◽  
Vaccine Candidate ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Wild Type ◽  
Live Attenuated Vaccine ◽  
Attenuated Vaccine ◽  
Western Africa

ABSTRACT Lassa virus (LASV) poses a significant public health problem within the regions of Lassa fever endemicity in Western Africa. LASV infects several hundred thousand individuals yearly, and a considerable number of Lassa fever cases are associated with high morbidity and lethality. No approved LASV vaccine is available, and current therapy is limited to an off-label usage of ribavirin that is only partially effective and associated with significant side effects. The impact of Lassa fever on human health, together with the limited existing countermeasures, highlights the importance of developing effective vaccines against LASV. Here, we present the development and characterization of a recombinant LASV (rLASV) vaccine candidate [rLASV(IGR/S-S)], which is based on the presence of the noncoding intergenic region (IGR) of the small (S) genome segment (S-IGR) in both large (L) and S LASV segments. In cultured cells, rLASV(IGR/S-S) was modestly less fit than wild-type rLASV (rLASV-WT). rLASV(IGR/S-S) was highly attenuated in guinea pigs, and a single subcutaneous low dose of the virus completely protected against otherwise lethal infection with LASV-WT. Moreover, rLASV(IGR/S-S) was genetically stable during serial passages in cultured cells. These findings indicate that rLASV(IGR/S-S) can be developed into a LASV live-attenuated vaccine (LAV) that has the same antigenic composition as LASV-WT and a well-defined mechanism of attenuation that overcomes concerns about increased virulence that could be caused by genetic changes in the LAV during multiple rounds of multiplication. IMPORTANCE Lassa virus (LASV), the causative agent of Lassa fever, infects several hundred thousand people in Western Africa, resulting in many lethal Lassa fever cases. No U.S. Food and Drug Administration-licensed countermeasures are available to prevent or treat LASV infection. We describe the generation of a novel LASV live-attenuated vaccine candidate rLASV(IGR/S-S), which is based on the replacement of the large genomic segment noncoding intergenic region (IGR) with that of the small genome segment. rLASV(IGR/S-S) is less fit in cell culture than wild-type virus and does not cause clinical signs in inoculated guinea pigs. Importantly, rLASV(IGR/S-S) protects immunized guinea pigs against an otherwise lethal exposure to LASV.

scholarly journals Elevated l-threonine is a biomarker for Lassa fever and Ebola

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Trevor V. Gale ◽  
John S. Schieffelin ◽  
Luis M. Branco ◽  
Robert F. Garry ◽  
Donald S. Grant
Keyword(s):  
Virus Infection ◽  
Prognostic Value ◽  
Ebola Virus ◽  
Platelet Activating Factor ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Liquid Chromatography Mass Spectrometry ◽  
Hemorrhagic Fevers ◽  
Viral Hemorrhagic Fevers ◽  
Ebola Virus Infection

Abstract Background Lassa fever and Ebola are characterized by non-specific initial presentations that can progress to severe multisystem illnesses with high fatality rates. Samples from additional subjects are examined to extend and corroborate biomarkers with prognostic value for these diseases. Methods Liquid Chromatography Mass Spectrometry metabolomics was used to identify and confirm metabolites disrupted in the blood of Lassa fever and Ebola patients. Authenticated standards are used to confirm the identify of key metabolites. Results We confirm prior results by other investigators that the amino acid l-threonine is elevated during Ebola virus infection. l-Threonine is also elevated during Lassa virus infection. We also confirmed that platelet-activating factor (PAF) and molecules with PAF moiety are reduced in the blood of patients with fatal Lassa fever. Similar changes in PAF and PAF-like molecules were not observed in the blood of Ebola patients. Conclusions Metabolomics may provide tools to identify pathways that are differentially affected during viral hemorrhagic fevers and guide development of diagnostics to monitor and predict outcome.

scholarly journals Systemic viral spreading and defective host responses are associated with fatal Lassa fever in macaques

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicolas Baillet ◽  
Stéphanie Reynard ◽  
Emeline Perthame ◽  
Jimmy Hortion ◽  
Alexandra Journeaux ◽  
...  
Keyword(s):  
T Cell ◽  
Multiorgan Failure ◽  
Severe Disease ◽  
T Cell Responses ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Diagnostic Tools ◽  
Lassa Virus ◽  
Full Characterization ◽  
Cell Responses

AbstractLassa virus (LASV) is endemic in West Africa and induces a viral hemorrhagic fever (VHF) with up to 30% lethality among clinical cases. The mechanisms involved in control of Lassa fever or, in contrast, the ensuing catastrophic illness and death are poorly understood. We used the cynomolgus monkey model to reproduce the human disease with asymptomatic to mild or fatal disease. After initial replication at the inoculation site, LASV reached the secondary lymphoid organs. LASV did not spread further in nonfatal disease and was rapidly controlled by balanced innate and T-cell responses. Systemic viral dissemination occurred during severe disease. Massive replication, a cytokine/chemokine storm, defective T-cell responses, and multiorgan failure were observed. Clinical, biological, immunological, and transcriptomic parameters resembled those observed during septic-shock syndrome, suggesting that similar pathogenesis is induced during Lassa fever. The outcome appears to be determined early, as differentially expressed genes in PBMCs were associated with fatal and non-fatal Lassa fever outcome very early after infection. These results provide a full characterization and important insights into Lassa fever pathogenesis and could help to develop early diagnostic tools.

Favipiravir: A New Medication for the Ebola Virus Disease Pandemic

2014 ◽  
Vol 9 (1) ◽  
pp. 79-81 ◽  
Author(s):  
Takashi Nagata ◽  
Alan K. Lefor ◽  
Manabu Hasegawa ◽  
Masami Ishii
Keyword(s):  
Ebola Virus ◽  
H1n1 Virus ◽  
Virus Disease ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Clinical Use ◽  
Experimental Drugs ◽  
Argentine Hemorrhagic Fever ◽  
Antiviral Medication ◽  
Pandemic Influenza H1n1

AbstractThe purpose of this report is to advocate speedy approval and less stringent regulations for the use of experimental drugs such as favipiravir in emergencies. Favipiravir is a new antiviral medication that can be used in emerging viral pandemics such as Ebola virus, 2009 pandemic influenza H1N1 virus, Lassa fever, and Argentine hemorrhagic fever. Although favipiravir is one of the choices for the treatment of patients with Ebola virus, several concerns exist. First, a clinical trial of favipiravir in patients infected with the Ebola virus has not yet been conducted, and further studies are required. Second, favipiravir has a risk for teratogenicity and embryotoxicity. Therefore, the Ministry of Health, Welfare and Labor of Japan has approved this medication with strict regulations for its production and clinical use. However, owing to the emerging Ebola virus epidemic in West Africa, on August 15, 2014, the Minister of Health, Welfare and Labor of Japan approved the use of favipiravir, if needed. (Disaster Med Public Health Preparedness. 2014;0:1-3)

scholarly journals Current and Future Diagnostic Tests for Ebola Virus Disease

2016 ◽  
Vol 19 (4) ◽  
pp. 530 ◽  
Author(s):  
Bharti Singh ◽  
Advaita Ganguly ◽  
Hoon H Sunwoo
Keyword(s):  
Ebola Virus ◽  
Virus Disease ◽  
Detection System ◽  
Ebola Virus Disease ◽  
Health Concern ◽  
Public Health Concern ◽  
Endemic Diseases ◽  
Efficient Management ◽  
Major Outbreak ◽  
User Friendly

Ebola virus disease (EVD) is a major public health concern with a high mortality rate in infected individuals. Outbreaks of Ebola have been widespread—there is no rapid, sensitive, specific, and affordable diagnostic test for the virus, nor there is any treatment for the disease. Overlapping symptoms of other endemic diseases, such as malaria and cholera, make it difficult to diagnose EVD. For clinical management, outbreak investigation, and proper surveillance, EVD requires a detection system, which should be fast, sensitive, specific, efficient, affordable, and user-friendly with in-country staff. In this review, we discuss the current diagnostics available for Ebola screening, along with the limitations and key improvements necessary for a more robust system to facilitate efficient management in case of another major outbreak.

scholarly journals The deuce-ace of Lassa Fever, Ebola virus disease and COVID-19 simultaneous infections and epidemics in West Africa: clinical and public health implications

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Nnabueze Darlington Nnaji ◽  
Helen Onyeaka ◽  
Rine Christopher Reuben ◽  
Olivier Uwishema ◽  
Chinasa Valerie Olovo ◽  
...  
Keyword(s):  
Public Health ◽  
Disease Surveillance ◽  
Ebola Virus ◽  
Virus Disease ◽  
Healthcare Systems ◽  
Lassa Fever ◽  
Ebola Virus Disease ◽  
Simultaneous Occurrence ◽  
Population Mobility ◽  
Health Concerns

AbstractGlobally, the prevailing COVID-19 pandemic has caused unprecedented clinical and public health concerns with increasing morbidity and mortality. Unfortunately, the burden of COVID-19 in Africa has been further exacerbated by the simultaneous epidemics of Ebola virus disease (EVD) and Lassa Fever (LF) which has created a huge burden on African healthcare systems. As Africa struggles to contain the spread of the second (and third) waves of the COVID-19 pandemic, the number of reported cases of LF is also increasing, and recently, new outbreaks of EVD. Before the pandemic, many of Africa’s frail healthcare systems were already overburdened due to resource limitations in staffing and infrastructure, and also, multiple endemic tropical diseases. However, the shared epidemiological and pathophysiological features of COVID-19, EVD and LF as well their simultaneous occurrence in Africa may result in misdiagnosis at the onset of infection, an increased possibility of co-infection, and rapid and silent community spread of the virus(es). Other challenges include high population mobility across porous borders, risk of human-to-animal transmission and reverse zoonotic spread, and other public health concerns. This review highlights some major clinical and public health challenges toward responses to the COVID-19 pandemic amidst the deuce-ace of recurrent LF and EVD epidemics in Africa. Applying the One Health approach in infectious disease surveillance and preparedness is essential in mitigating emerging and re-emerging (co-)epidemics in Africa and beyond.

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