101
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Fatiregun AA, Isere EE. Epidemic preparedness and management: A guide on Lassa fever outbreak preparedness plan. Niger Med J 2017; 58:1-6. [PMID: 29238121 PMCID: PMC5715560 DOI: 10.4103/0300-1652.218414] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Epidemic prone diseases threaten public health security. These include diseases such as cholera, meningitis, and hemorrhagic fevers, especially Lassa fever for which Nigeria reports considerable morbidity and mortality annually. Interestingly, where emergency epidemic preparedness plans are in place, timely detection of outbreaks is followed by a prompt and appropriate response. Furthermore, due to the nature of spread of Lassa fever in an outbreak setting, there is the need for health-care workers to be familiar with the emerging epidemic management framework that has worked in other settings for effective preparedness and response. This paper, therefore, discussed the principles of epidemic management using an emergency operating center model, review the epidemiology of Lassa fever in Nigeria, and provide guidance on what is expected to be done in preparing for epidemic of the disease at the health facilities, local and state government levels in line with the Integrated Disease Surveillance and Response strategy.
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Affiliation(s)
| | - Elvis Efe Isere
- Cluster Coordinator, World Health Organization, Akure, Ondo State, Nigeria
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102
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Comparison of MagPix Assays and Enzyme-Linked Immunosorbent Assay for Detection of Hemorrhagic Fever Viruses. J Clin Microbiol 2016; 55:68-78. [PMID: 27795340 DOI: 10.1128/jcm.01693-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 09/26/2016] [Indexed: 11/20/2022] Open
Abstract
Viral hemorrhagic fevers, because of their high mortality rates, the lack of medical countermeasures, and their potential use as instruments of bioterrorism, pose a significant threat to the developed and the developing areas of the world. The key to preventing the spread of these diseases is early and accurate detection. For decades, the gold-standard immunoassay for hemorrhagic fever detection has been the enzyme-linked immunosorbent assay (ELISA); however, newer technologies are emerging with increased sensitivities. One such technology is the Luminex MagPix platform using xMAP microspheres. Here, we compare the MagPix platform with a traditional ELISA for IgM and antigen detection of infections from Lassa and Ebola viruses (LASV and EBOV, respectively). For IgM detection in nonhuman primate samples, the MagPix platform was 5 and 25 times more sensitive in detecting LASV and EBOV, respectively, compared to that with ELISA. For antigen detection in buffer, the MagPix platform was 25 and 2.5 times more sensitive in detecting lower levels of LASV and EBOV, respectively. In both IgM and antigen detection assays, the MagPix platform demonstrated excellent reproducibility at the lower limit of detection (LLOD). These findings demonstrate that the MagPix platform is a viable diagnostic replacement for the ELISA for viral hemorrhagic fevers.
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103
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Sogoba N, Rosenke K, Adjemian J, Diawara SI, Maiga O, Keita M, Konaté D, Keita AS, Sissoko I, Boisen M, Nelson D, Oottamasathien D, Millett M, Garry RF, Branco LM, Traoré SF, Doumbia S, Feldmann H, Safronetz D. Lassa Virus Seroprevalence in Sibirilia Commune, Bougouni District, Southern Mali. Emerg Infect Dis 2016; 22:657-63. [PMID: 26981786 PMCID: PMC4806955 DOI: 10.3201/eid2204.151814] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The high rate documented in this study highlights the need for increased surveillance. Lassa Virus Seroprevalence, Mali Lassa virus (LASV) is endemic to several nations in West Africa. In Mali, LASV was unknown until an exported case of Lassa fever was reported in 2009. Since that time, rodent surveys have found evidence of LASV-infected Mastomys natalensis rats in several communities in southern Mali, near the border with Côte d’Ivoire. Despite increased awareness, to date only a single case of Lassa fever has been confirmed in Mali. We conducted a survey to determine the prevalence of LASV exposure among persons in 3 villages in southern Mali where the presence of infected rodents has been documented. LASV IgG seroprevalence ranged from 14.5% to 44% per village. No sex bias was noted; however, seropositivity rates increased with participant age. These findings confirm human LASV exposure in Mali and suggest that LASV infection/Lassa fever is a potential public health concern in southern Mali.
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104
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Arkell P, Youkee D, Brown CS, Kamara A, Kamara TB, Johnson O, Lado M, George V, Koroma F, King MB, Parker BE, Baker P. Quantifying the risk of nosocomial infection within Ebola Holding Units: a retrospective cohort study of negative patients discharged from five Ebola Holding Units in Western Area, Sierra Leone. Trop Med Int Health 2016; 22:32-40. [PMID: 27782349 DOI: 10.1111/tmi.12802] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES A central pillar in the response to the 2014 Ebola virus disease (EVD) epidemic in Sierra Leone was the role of Ebola Holding Units (EHUs). These units isolated patients meeting a suspect case definition, tested them for EVD, initiated appropriate early treatment and discharged negative patients to onward inpatient care or home. Positive patients were referred to Ebola Treatment Centres. We aimed to estimate the risk of nosocomial transmission within these EHUs. METHODS We followed up a cohort of 543 patients discharged with a negative EVD test from five EHUs in the Western Area, Sierra Leone, and examined all line-listed subsequent EVD tests from any facility in the Western Area to see whether the patient was retested within 30 days, matching by name, age and address. We defined possible readmissions as having the same name and age but uncertain address, and confirmed readmissions where name, age and address matched. RESULTS We found a positive readmission rate of 3.3% (18 cases), which included 1.5% confirmed readmissions (8 cases) and 1.8% possible readmissions (10 cases). This is lower than rates previously reported. We cannot ascertain whether EVD was acquired within the EHUs or from re-exposure in the community. No demographic or clinical variables were identified as risk factors for positive readmission, likely due to our small sample size. CONCLUSIONS These findings support the EHU model as a safe method for isolation of suspect EVD patients and their role in limiting the spread of EVD.
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Affiliation(s)
- Paul Arkell
- King's Sierra Leone Partnership, King's College London, London, UK
| | - Daniel Youkee
- King's Sierra Leone Partnership, King's College London, London, UK
| | - Colin S Brown
- King's Sierra Leone Partnership, King's College London, London, UK.,Hospital for Tropical Diseases, University College Hospital London, London, UK
| | - Abdul Kamara
- Republic of Sierra Leone Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Oliver Johnson
- King's Sierra Leone Partnership, King's College London, London, UK
| | - Marta Lado
- King's Sierra Leone Partnership, King's College London, London, UK
| | | | | | | | | | - Peter Baker
- King's Sierra Leone Partnership, King's College London, London, UK.,Department of Primary Care and Public Health, Imperial College London, London, UK
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105
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Ehlkes L, Kreuels B, Schwarz NG, May J. [Epidemiology of Ebola virus disease and of other highly contagious, life-threatening diseases with low incidence in Germany]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2016; 58:705-13. [PMID: 25997608 PMCID: PMC7080030 DOI: 10.1007/s00103-015-2165-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Das Vorkommen von Ebolafieber, der Marburgvirus-Krankheit sowie von Lassa-Fieber ist – abgesehen von vereinzelten eingeschleppten Fällen – auf den afrikanischen Kontinent beschränkt. Hämorrhagisches Krim-Kongo-Fieber kommt in Südosteuropa, jedoch bisher nicht in Deutschland vor. Weitere hämorrhagische Fiebererkrankungen sind regional auf dem südamerikanischen Kontinent verbreitet. Die Lungenpest ist die bakterielle Infektionskrankheit mit der höchsten Kontagiösität und Letalität und ist vor allem in Madagaskar und Ostafrika, aber auch in vielen anderen Ländern beheimatet, wie z. B. in Indien und in den USA. Affenpocken haben in entlegenen Regionen des Kongobeckens zu Ausbrüchen geführt, die sich in Zukunft aufgrund der nicht mehr durchgeführten Pockenimpfung häufen könnten. Das 2002/2003 neu aufgetretene Severe Acute Respiratory Syndrome (SARS) ist eine weitere Erkrankung mit hohem epidemischen Potenzial. Typisch für diese hochkontagiösen Erreger ist, dass sie meist unerkannt zwischen Reservoirtieren abseits des Menschen zirkulieren. Durch sporadischen Kontakt zwischen infizierten Tieren und dem Menschen können diese übertragen werden. Die dann folgende Mensch-zu-Mensch-Übertragung kann zu ausgedehnten Epidemien, wie dem derzeitigen Ausbruch des Ebolafiebers in Westafrika, führen.
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Affiliation(s)
- L Ehlkes
- Arbeitsgruppe Infektionsepidemiologie, Bernhard-Nocht-Institut für Tropenmedizin (BNITM), Bernhard-Nocht-Str. 74, 20359, Hamburg, Deutschland
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106
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Okokhere PO, Bankole IA, Iruolagbe CO, Muoebonam BE, Okonofua MO, Dawodu SO, Akpede GO. Aseptic Meningitis Caused by Lassa Virus: Case Series Report. Case Rep Neurol Med 2016; 2016:1978461. [PMID: 27957363 PMCID: PMC5124455 DOI: 10.1155/2016/1978461] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 10/13/2016] [Indexed: 11/17/2022] Open
Abstract
The Lassa virus is known to cause disease in different organ systems of the human body, with varying clinical manifestations. The features of severe clinical disease may include bleeding and/or central nervous system manifestations. Whereas Lassa fever encephalopathy and encephalitis are well described in the literature, there is paucity of data on Lassa virus meningitis. We present the clinical description, laboratory diagnosis, and management of 4 consecutive cases of aseptic meningitis associated with Lassa virus infection without bleeding seen in a region of Nigeria known to be endemic for both the reservoir rodent and Lassa fever. The 4 patients recovered fully following intravenous ribavirin treatment and suffered no neurologic complications.
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Affiliation(s)
- Peter O. Okokhere
- Department of Medicine, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
| | - Idowu A. Bankole
- Department of Medicine, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
| | | | - Benard E. Muoebonam
- Institute of Lassa fever Research and Control, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
| | - Martha O. Okonofua
- Lassa Fever Ward, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
| | - Simeon O. Dawodu
- Department of Paediatrics, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
| | - George O. Akpede
- Department of Paediatrics, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
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107
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Genome Sequence of Lassa Virus Isolated from the First Domestically Acquired Case in Germany. GENOME ANNOUNCEMENTS 2016; 4:4/5/e00938-16. [PMID: 27660771 PMCID: PMC5034122 DOI: 10.1128/genomea.00938-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Lassa virus (LASV) is a zoonotic, hemorrhagic fever-causing virus endemic in West Africa, for which no approved vaccines or specific treatment options exist. Here, we report the genome sequence of LASV isolated from the first case of acquired Lassa fever disease outside of Africa.
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108
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Isa SE, Okwute A, Iraoyah KO, Nathan SY, Simji GS, Okolo MO, Anejo-Okopi J, Spicola D, Isa DE. Postexposure prophylaxis for Lassa fever: Experience from a recent outbreak in Nigeria. Niger Med J 2016; 57:246-50. [PMID: 27630390 PMCID: PMC4995818 DOI: 10.4103/0300-1652.188362] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background: Secondary transmission of Lassa fever (LF) occurs in the community and in health-care facilities, and is associated with high fatality in Nigeria. We investigated the role of oral ribavirin postexposure prophylaxis (orPEP) in preventing LF among the primary contacts of confirmed cases from December 2015 to March 2016. Materials and Methods: Epidemiological and clinical data of LF contacts were prospectively collected. However, information regarding ribavirin adverse effects (AEs) were collected retrospectively through a telephone interview. High-risk contacts were clinically monitored orPEP. Results: Thirty-five (94.6%) out of the 37 individuals enrolled in the study were contacts of confirmed LF cases, and friends and family members (54%) constituted the largest group. However, only 29 (83%) individuals were classified as high-risk contacts. Twenty-one (60%) of contacts were prescribed ribavirin with 6 (28.6%) of them reporting AEs. Body weakness (33%) was the most frequent AE, but there was no incidence of treatment discontinuation due to AE. Furthermore, there were no reported cases of LF among all respondents (0%), whether they had orPEP or not. Conclusion: Secondary transmission of LF seems uncommon and the benefit of orPEP is uncertain. Although AEs of ribavirin may not be uncommon, they are rarely serious enough to cause treatment interruption. More emphasis should be on supporting persons looking after LF cases adopt measures that minimize the risks of exposure.
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Affiliation(s)
- Samson E Isa
- Department of Medicine, Infectious Diseases Unit, University of Jos/Jos University Teaching Hospital, Jos, Plateau State, Nigeria
| | - Attah Okwute
- Department of Medicine, Infectious Diseases Unit, University of Jos/Jos University Teaching Hospital, Jos, Plateau State, Nigeria
| | - Kelly O Iraoyah
- Department of Medicine, Infectious Diseases Unit, University of Jos/Jos University Teaching Hospital, Jos, Plateau State, Nigeria
| | - Shehu Y Nathan
- Department of Medicine, Infectious Diseases Unit, University of Jos/Jos University Teaching Hospital, Jos, Plateau State, Nigeria
| | - Gomerep S Simji
- Department of Medicine, Infectious Diseases Unit, University of Jos/Jos University Teaching Hospital, Jos, Plateau State, Nigeria
| | - Mark O Okolo
- Department of Medical Microbiology, University of Jos/Jos University Teaching Hospital, Jos, Plateau State, Nigeria
| | - Joseph Anejo-Okopi
- Department of Microbiology, University of Jos, Jos, Plateau State, Nigeria
| | - Daria Spicola
- Department of Internal Medicine, Infectious Diseases Unit, Arnas Civico Di Cristina Benfratelli, Palermo, Italy
| | - Daisy E Isa
- Department of Pharmaceutical Sciences, Aston University, Birmingham, United Kingdom
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109
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Weber DJ, Rutala WA, Fischer WA, Kanamori H, Sickbert-Bennett EE. Emerging infectious diseases: Focus on infection control issues for novel coronaviruses (Severe Acute Respiratory Syndrome-CoV and Middle East Respiratory Syndrome-CoV), hemorrhagic fever viruses (Lassa and Ebola), and highly pathogenic avian influenza viruses, A(H5N1) and A(H7N9). Am J Infect Control 2016; 44:e91-e100. [PMID: 27131142 PMCID: PMC7132650 DOI: 10.1016/j.ajic.2015.11.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 11/11/2015] [Indexed: 01/01/2023]
Abstract
Over the past several decades, we have witnessed the emergence of many new infectious agents, some of which are major public threats. New and emerging infectious diseases which are both transmissible from patient-to-patient and virulent with a high mortality include novel coronaviruses (SARS-CoV, MERS-CV), hemorrhagic fever viruses (Lassa, Ebola), and highly pathogenic avian influenza A viruses, A(H5N1) and A(H7N9). All healthcare facilities need to have policies and plans in place for early identification of patients with a highly communicable diseases which are highly virulent, ability to immediately isolate such patients, and provide proper management (e.g., training and availability of personal protective equipment) to prevent transmission to healthcare personnel, other patients and visitors to the healthcare facility.
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Affiliation(s)
- David J Weber
- Department of Hospital Epidemiology, University of North Carolina Health Care, Chapel Hill, NC; Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC.
| | - William A Rutala
- Department of Hospital Epidemiology, University of North Carolina Health Care, Chapel Hill, NC; Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC
| | - William A Fischer
- Division of Pulmonary and Critical Care Medicine, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Hajime Kanamori
- Department of Hospital Epidemiology, University of North Carolina Health Care, Chapel Hill, NC; Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Emily E Sickbert-Bennett
- Department of Hospital Epidemiology, University of North Carolina Health Care, Chapel Hill, NC; Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC
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110
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Brosh-Nissimov T. Lassa fever: another threat from West Africa. DISASTER AND MILITARY MEDICINE 2016; 2:8. [PMID: 28265442 PMCID: PMC5330145 DOI: 10.1186/s40696-016-0018-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/23/2016] [Indexed: 12/18/2022]
Abstract
Lassa fever, a zoonotic viral infection, is endemic in West Africa. The disease causes annual wide spread morbidity and mortality in Africa, and can be imported by travelers. Possible importation of Lassa fever and the potential for the use of Lassa virus as an agent of bioterrorism mandate clinicians in Israel and other countries to be vigilant and familiar with the basic characteristics of this disease. The article reviews the basis of this infection and the clinical management of patients with Lassa fever. Special emphasis is given to antiviral treatment and infection control.
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111
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Mofolorunsho KC. Outbreak of lassa fever in Nigeria: measures for prevention and control. Pan Afr Med J 2016; 23:210. [PMID: 27347299 PMCID: PMC4907747 DOI: 10.11604/pamj.2016.23.210.8923] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/10/2016] [Indexed: 11/11/2022] Open
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112
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Native functionality and therapeutic targeting of arenaviral glycoproteins. Curr Opin Virol 2016; 18:70-5. [PMID: 27104809 DOI: 10.1016/j.coviro.2016.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/08/2016] [Accepted: 04/01/2016] [Indexed: 12/31/2022]
Abstract
Surface glycoproteins direct cellular targeting, attachment, and membrane fusion of arenaviruses and are the primary target for neutralizing antibodies. Despite significant conservation of the glycoprotein architecture across the arenavirus family, there is considerable variation in the molecular recognition mechanisms used during host cell entry. We review recent progress in dissecting these infection events and describe how arenaviral glycoproteins can be targeted by small-molecule antivirals, the natural immune response, and immunoglobulin-based therapeutics. Arenaviral glycoprotein-mediated assembly and infection pathways present numerous opportunities and challenges for therapeutic intervention.
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113
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Youkee D, Brown CS, Lilburn P, Shetty N, Brooks T, Simpson A, Bentley N, Lado M, Kamara TB, Walker NF, Johnson O. Assessment of Environmental Contamination and Environmental Decontamination Practices within an Ebola Holding Unit, Freetown, Sierra Leone. PLoS One 2015; 10:e0145167. [PMID: 26692018 PMCID: PMC4687095 DOI: 10.1371/journal.pone.0145167] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/30/2015] [Indexed: 12/21/2022] Open
Abstract
Evidence to inform decontamination practices at Ebola holding units (EHUs) and treatment centres is lacking. We conducted an audit of decontamination procedures inside Connaught Hospital EHU in Freetown, Sierra Leone, by assessing environmental swab specimens for evidence of contamination with Ebola virus by RT-PCR. Swabs were collected following discharge of Ebola Virus Disease (EVD) patients before and after routine decontamination. Prior to decontamination, Ebola virus RNA was detected within a limited area at all bedside sites tested, but not at any sites distant to the bedside. Following decontamination, few areas contained detectable Ebola virus RNA. In areas beneath the bed there was evidence of transfer of Ebola virus material during cleaning. Retraining of cleaning staff reduced evidence of environmental contamination after decontamination. Current decontamination procedures appear to be effective in eradicating persistence of viral RNA. This study supports the use of viral swabs to assess Ebola viral contamination within the clinical setting. We recommend that regular refresher training of cleaning staff and audit of environmental contamination become standard practice at all Ebola care facilities during EVD outbreaks.
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Affiliation(s)
- Daniel Youkee
- King’s Sierra Leone Partnership, King's Centre for Global Health, King's College London, and King’s Health Partners, London, United Kingdom
| | - Colin S. Brown
- King’s Sierra Leone Partnership, King's Centre for Global Health, King's College London, and King’s Health Partners, London, United Kingdom
- The Hospital for Tropical Diseases, University College London Hospitals, London, United Kingdom
| | - Paul Lilburn
- King’s Sierra Leone Partnership, King's Centre for Global Health, King's College London, and King’s Health Partners, London, United Kingdom
| | | | - Tim Brooks
- Public Health England, Salisbury, United Kingdom
| | | | - Neil Bentley
- Public Health England, Salisbury, United Kingdom
| | - Marta Lado
- King’s Sierra Leone Partnership, King's Centre for Global Health, King's College London, and King’s Health Partners, London, United Kingdom
| | | | - Naomi F. Walker
- King’s Sierra Leone Partnership, King's Centre for Global Health, King's College London, and King’s Health Partners, London, United Kingdom
- Department of Infectious Diseases and Immunity, Imperial College London, London, United Kingdom
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Oliver Johnson
- King’s Sierra Leone Partnership, King's Centre for Global Health, King's College London, and King’s Health Partners, London, United Kingdom
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114
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The broad-spectrum antiviral favipiravir protects guinea pigs from lethal Lassa virus infection post-disease onset. Sci Rep 2015; 5:14775. [PMID: 26456301 PMCID: PMC4600983 DOI: 10.1038/srep14775] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/07/2015] [Indexed: 01/25/2023] Open
Abstract
With up to 500,000 infections annually, Lassa virus (LASV), the cause of Lassa fever, is one of the most prevalent etiological agents of viral hemorrhagic fever (VHF) in humans. LASV is endemic in several West African countries with sporadic cases and prolonged outbreaks observed most commonly in Sierra Leone, Liberia, Guinea and Nigeria. Additionally several cases of Lassa fever have been imported into North America, Europe and Asia making LASV a global threat to public health. Despite this, currently no approved therapeutic or vaccine exists to treat or prevent LASV infections. Here, using a passaged strain of LASV that is uniformly lethal in Hartley guinea pigs, we demonstrate that favipiravir, a broad-spectrum antiviral agent and leading treatment option for influenza, has potent activity against LASV infection. In this model, once daily treatment with favipiravir significantly reduced viral titers in tissue samples and reduced mortality rates when compared with animals receiving vehicle-only or ribavirin, the current standard of care for Lassa fever. Favipiravir remained highly effective against lethal LASV infection when treatments were initiated nine days post-infection, a time when animals were demonstrating advanced signs of disease. These results support the further preclinical evaluation of favipiravir for Lassa fever and other VHFs.
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115
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Schieffelin J. Treatment of Arenavirus Infections. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2015. [DOI: 10.1007/s40506-015-0058-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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116
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Messina JP, Pigott DM, Golding N, Duda KA, Brownstein JS, Weiss DJ, Gibson H, Robinson TP, Gilbert M, William Wint GR, Nuttall PA, Gething PW, Myers MF, George DB, Hay SI. The global distribution of Crimean-Congo hemorrhagic fever. Trans R Soc Trop Med Hyg 2015; 109:503-13. [PMID: 26142451 PMCID: PMC4501401 DOI: 10.1093/trstmh/trv050] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne infection caused by a virus (CCHFV) from the Bunyaviridae family. Domestic and wild vertebrates are asymptomatic reservoirs for the virus, putting animal handlers, slaughter-house workers and agricultural labourers at highest risk in endemic areas, with secondary transmission possible through contact with infected blood and other bodily fluids. Human infection is characterized by severe symptoms that often result in death. While it is known that CCHFV transmission is limited to Africa, Asia and Europe, definitive global extents and risk patterns within these limits have not been well described. METHODS We used an exhaustive database of human CCHF occurrence records and a niche modeling framework to map the global distribution of risk for human CCHF occurrence. RESULTS A greater proportion of shrub or grass land cover was the most important contributor to our model, which predicts highest levels of risk around the Black Sea, Turkey, and some parts of central Asia. Sub-Saharan Africa shows more focalized areas of risk throughout the Sahel and the Cape region. CONCLUSIONS These new risk maps provide a valuable starting point for understanding the zoonotic niche of CCHF, its extent and the risk it poses to humans.
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Affiliation(s)
| | | | - Nick Golding
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - John S Brownstein
- Department of Pediatrics, Harvard Medical School and Children's Hospital Informatics Program, Boston Children's Hospital, Boston, MA, USA
| | | | - Harry Gibson
- Department of Zoology, University of Oxford, Oxford, UK
| | - Timothy P Robinson
- Livestock Systems and Environment (LSE), International Livestock Research Institute (ILRI),Nairobi, Kenya
| | - Marius Gilbert
- Biological Control and Spatial Ecology, Université Libre de Bruxelles, Brussels, Belgium Fonds National de la Recherche Scientifique, Brussels, Belgium
| | | | | | | | | | - Dylan B George
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - Simon I Hay
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK Fogarty International Center, National Institutes of Health, Bethesda, MD, USA Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
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117
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Iroezindu MO, Unigwe US, Okwara CC, Ozoh GA, Ndu AC, Ohanu ME, Nwoko UO, Okoroafor UW, Ejimudo E, Tobin EA, Asogun DA. Lessons learnt from the management of a case of Lassa fever and follow-up of nosocomial primary contacts in Nigeria during Ebola virus disease outbreak in West Africa. Trop Med Int Health 2015; 20:1424-1430. [PMID: 26171669 DOI: 10.1111/tmi.12565] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To describe our experiences in the management of a case of Lassa fever (LF) and follow-up of nosocomial primary contacts during the 2014 Ebola outbreak in West Africa. METHODS Clinical management of the index case and infection control/surveillance activities for primary contacts are described. Laboratory confirmation was by Lassa virus-specific reverse-transcriptase PCR. RESULTS A 28-year-old man with a 10-day history of febrile illness was referred to a major tertiary hospital in south-east Nigeria from a city that previously experienced a LF outbreak and was recently affected by Ebola. On observation of haemorrhagic features, clinicians were at a crossroads. Diagnosis of LF was confirmed at a National Reference Centre. The patient died despite initiation of ribavirin therapy. Response activities identified 121 primary contacts comprising 78 (64.5%) hospital staff/interns, 19 (15.7%) medical students, 18 (14.9%) inpatients and 6 (5.0%) relatives. Their mean age was 32.8 ± 6.6 years, and 65.3% were women. Twenty (16.5%) had high-risk exposure and were offered ribavirin as post-exposure prophylaxis. No secondary case of LF occurred. Fatigue (43.8%) and dizziness (31.3%) were the commonest side effects of ribavirin. CONCLUSIONS Response activities contained nosocomial spread of LF, but challenges were experienced including lack of a purpose-built isolation facility, absence of local Lassa virus laboratory capacity, failure to use appropriate protective equipment and stigmatisation of contacts. A key lesson is that the weak health systems of Africa should be comprehensively strengthened; otherwise, we might win the Ebola battle but lose the one against less virulent infections for which effective treatment exists.
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Affiliation(s)
- Michael O Iroezindu
- Department of Medicine, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Uche S Unigwe
- Department of Medicine, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Celestine C Okwara
- Department of Medicine, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Gladys A Ozoh
- Department of Medicine, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Anne C Ndu
- Department of Community Medicine, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Martin E Ohanu
- Department of Medical Microbiology, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Ugochukwu O Nwoko
- Department of Medicine, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Uwadiegwu W Okoroafor
- Department of Medicine, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria
| | - Esinulo Ejimudo
- Nigeria Centre for Disease Control and Prevention, Abuja, Nigeria
| | - Ekaete A Tobin
- Institute of Lassa Fever Research and Control, Irrua Specialist Hospital, Irrua, Edo State, Nigeria
| | - Danny A Asogun
- Institute of Lassa Fever Research and Control, Irrua Specialist Hospital, Irrua, Edo State, Nigeria
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Animal Models for the Study of Rodent-Borne Hemorrhagic Fever Viruses: Arenaviruses and Hantaviruses. BIOMED RESEARCH INTERNATIONAL 2015; 2015:793257. [PMID: 26266264 PMCID: PMC4523679 DOI: 10.1155/2015/793257] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/14/2015] [Indexed: 11/20/2022]
Abstract
Human pathogenic hantaviruses and arenaviruses are maintained in nature by persistent infection of rodent carrier populations. Several members of these virus groups can cause significant disease in humans that is generically termed viral hemorrhagic fever (HF) and is characterized as a febrile illness with an increased propensity to cause acute inflammation. Human interaction with rodent carrier populations leads to infection. Arenaviruses are also viewed as potential biological weapons threat agents. There is an increased interest in studying these viruses in animal models to gain a deeper understating not only of viral pathogenesis, but also for the evaluation of medical countermeasures (MCM) to mitigate disease threats. In this review, we examine current knowledge regarding animal models employed in the study of these viruses. We include analysis of infection models in natural reservoirs and also discuss the impact of strain heterogeneity on the susceptibility of animals to infection. This information should provide a comprehensive reference for those interested in the study of arenaviruses and hantaviruses not only for MCM development but also in the study of viral pathogenesis and the biology of these viruses in their natural reservoirs.
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119
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Mylne AQN, Pigott DM, Longbottom J, Shearer F, Duda KA, Messina JP, Weiss DJ, Moyes CL, Golding N, Hay SI. Mapping the zoonotic niche of Lassa fever in Africa. Trans R Soc Trop Med Hyg 2015; 109:483-92. [PMID: 26085474 PMCID: PMC4501400 DOI: 10.1093/trstmh/trv047] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/29/2015] [Indexed: 02/05/2023] Open
Abstract
Background Lassa fever is a viral haemorrhagic illness responsible for disease outbreaks across West Africa. It is a zoonosis, with the primary reservoir species identified as the Natal multimammate mouse, Mastomys natalensis. The host is distributed across sub-Saharan Africa while the virus' range appears to be restricted to West Africa. The majority of infections result from interactions between the animal reservoir and human populations, although secondary transmission between humans can occur, particularly in hospital settings. Methods Using a species distribution model, the locations of confirmed human and animal infections with Lassa virus (LASV) were used to generate a probabilistic surface of zoonotic transmission potential across sub-Saharan Africa. Results Our results predict that 37.7 million people in 14 countries, across much of West Africa, live in areas where conditions are suitable for zoonotic transmission of LASV. Four of these countries, where at-risk populations are predicted, have yet to report any cases of Lassa fever. Conclusions These maps act as a spatial guide for future surveillance activities to better characterise the geographical distribution of the disease and understand the anthropological, virological and zoological interactions necessary for viral transmission. Combining this zoonotic niche map with detailed patient travel histories can aid differential diagnoses of febrile illnesses, enabling a more rapid response in providing care and reducing the risk of onward transmission.
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Affiliation(s)
- Adrian Q N Mylne
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Joshua Longbottom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Freya Shearer
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | | | | | - Catherine L Moyes
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Nick Golding
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Simon I Hay
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK Institute for Health Metrics and Evaluation, University of Washington, Seattle, USA Fogarty International Center, National Institutes of Health, Bethesda, Maryland, USA
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120
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Findlay JS, Ulaeto D, D'Elia RV. Cytokines and viral hemorrhagic fever: potential for therapeutic intervention. Future Virol 2015. [DOI: 10.2217/fvl.15.5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT The recent Ebola outbreak in West Africa highlights the need to improve our understanding of why viral hemorrhagic fevers (VHFs) are so devastating. There is a requirement to generate effective prophylactics, such as vaccines, and therapies, especially those that are effective postsymptomatically. For a range of pathogens, it appears that overstimulation of pro-inflammatory cytokines, the ‘cytokine storm’, causes serious immunopathology in patients. In this review, we will focus on the cytokine response following infection by representatives of the viruses which can cause VHF: Ebola virus and Marburg virus, Crimean–Congo hemorrhagic fever virus, Dengue virus, Junin and Lassa virus. Specifically, the role of the cytokine storm in causing VHF and the use of therapeutic immunomodulatory compounds to help treat these fatal and debilitating diseases will be explored.
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Affiliation(s)
- James S Findlay
- Biomedical Sciences, Defence Science & Technology Laboratory (Dstl) Porton Down, Salisbury, SP4 0JQ, UK
| | - David Ulaeto
- Biomedical Sciences, Defence Science & Technology Laboratory (Dstl) Porton Down, Salisbury, SP4 0JQ, UK
| | - Riccardo V D'Elia
- Biomedical Sciences, Defence Science & Technology Laboratory (Dstl) Porton Down, Salisbury, SP4 0JQ, UK
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Hartnett JN, Boisen ML, Oottamasathien D, Jones AB, Millett MM, Nelson DS, Muncy IJ, Goba A, Momoh M, Fullah M, Mire CE, Geisbert JB, Geisbert TW, Holton DL, Rouelle JA, Kannadka CB, Reyna AA, Moses LM, Khan SH, Gevao SM, Grant DS, Robinson JE, Happi C, Pitts KR, Garry RF, Branco LM. Current and emerging strategies for the diagnosis, prevention and treatment of Lassa fever. Future Virol 2015. [DOI: 10.2217/fvl.15.41] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
ABSTRACT Lassa fever (LF) is a potentially fatal disease that affects an estimated 300,000–500,000 people in endemic areas of west Africa each year. Though past studies have identified fatality rates of 5–20% in patients suspected to have contracted Lassa virus (LASV), new studies using more precise clinical diagnoses and modern diagnostic assays show fatalities rates above 60% in acutely ill patients from endemic regions. Currently, there are no approved vaccines or therapeutics, and only one Comformité Européenne (CE) marked rapid immunodiagnostic for acute LASV infection. Therefore, preventing LASV transmission is the primary goal in endemic regions. Development of rapid immunodiagnostics and research into the efficacy of current treatment options continues toward saving lives in west Africa as well as creating a line of defense against the nefarious use of LASV in bioterrorism settings.
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Affiliation(s)
- Jessica N Hartnett
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
| | - Matthew L Boisen
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
- Corgenix Medical Corporation, Broomfield, CO 80020, USA
| | | | | | | | | | - Ivana J Muncy
- Corgenix Medical Corporation, Broomfield, CO 80020, USA
| | | | - Mambu Momoh
- Kenema Government Hospital, Kenema, Sierra Leone
- Eastern Polytechnic College, Kenema, Sierra Leone
| | | | - Chad E Mire
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Joan B Geisbert
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Thomas W Geisbert
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Debra L Holton
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
| | - Julie A Rouelle
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
| | - Chandrika B Kannadka
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
| | - Ashley A Reyna
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
| | - Lina M Moses
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
| | | | - Sahr M Gevao
- Ministry of Health and Sanitation, Freetown, Sierra Leone
- University of Sierra Leone, Freetown, Sierra Leone
| | - Donald S Grant
- Kenema Government Hospital, Kenema, Sierra Leone
- Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - James E Robinson
- Department of Pediatric Infectious Diseases, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | | | - Kelly R Pitts
- Corgenix Medical Corporation, Broomfield, CO 80020, USA
| | - Robert F Garry
- Department of Microbiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA
- Zalgen Labs, LLC, Germantown, MD 20876, USA
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A recombinant vesicular stomatitis virus-based Lassa fever vaccine protects guinea pigs and macaques against challenge with geographically and genetically distinct Lassa viruses. PLoS Negl Trop Dis 2015; 9:e0003736. [PMID: 25884628 PMCID: PMC4401668 DOI: 10.1371/journal.pntd.0003736] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/02/2015] [Indexed: 11/19/2022] Open
Abstract
Background Lassa virus (LASV) is endemic in several West African countries and is the etiological agent of Lassa fever. Despite the high annual incidence and significant morbidity and mortality rates, currently there are no approved vaccines to prevent infection or disease in humans. Genetically, LASV demonstrates a high degree of diversity that correlates with geographic distribution. The genetic heterogeneity observed between geographically distinct viruses raises concerns over the potential efficacy of a “universal” LASV vaccine. To date, several experimental LASV vaccines have been developed; however, few have been evaluated against challenge with various genetically unique Lassa virus isolates in relevant animal models. Methodologies/principle findings Here we demonstrate that a single, prophylactic immunization with a recombinant vesicular stomatitis virus (VSV) expressing the glycoproteins of LASV strain Josiah from Sierra Leone protects strain 13 guinea pigs from infection / disease following challenge with LASV isolates originating from Liberia, Mali and Nigeria. Similarly, the VSV-based LASV vaccine yields complete protection against a lethal challenge with the Liberian LASV isolate in the gold-standard macaque model of Lassa fever. Conclusions/significance Our results demonstrate the VSV-based LASV vaccine is capable of preventing morbidity and mortality associated with non-homologous LASV challenge in two animal models of Lassa fever. Additionally, this work highlights the need for the further development of disease models for geographical distinct LASV strains, particularly those from Nigeria, in order to comprehensively evaluate potential vaccines and therapies against this prominent agent of viral hemorrhagic fever. Lassa fever (LF) is an acute viral infection which is often associated with hemorrhagic manifestations and multi-organ failure in humans. The etiological agent responsible for LF is Lassa virus (LASV), a rodent-borne Arenavirus which is endemic in several West African countries. Up to 500,000 cases of LF are diagnosed annually, primarily in Nigeria, Liberia, Guinea and Sierra Leone. The high incidence rate combined with the significant morbidity and mortality associated with LASV infection highlights the need for an effective prophylactic vaccine for LF. Importantly, an ideal LASV vaccine should provide protection against genetically and geographical divergent viral strains. Previously a recombinant vesicular stomatitis virus (VSV)-based LF vaccine using the glycoproteins of LASV strain Josiah as the immunogen, was shown to completely protect non-human primates against a homologous (LASV strain Josiah) challenge. Here, we have expanded the original studies and tested the VSV-LASV vaccine against challenge with LASV isolates from Mali, Liberia and Nigeria in the strain 13 guinea pig and cynomolgus macaque disease models. Our results suggest that the VSV-based LF vaccine affords complete protection against geographically and genetically distinct viral isolates.
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123
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Shears P, O'Dempsey TJD. Ebola virus disease in Africa: epidemiology and nosocomial transmission. J Hosp Infect 2015; 90:1-9. [PMID: 25655197 DOI: 10.1016/j.jhin.2015.01.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/11/2015] [Indexed: 10/24/2022]
Abstract
The 2014 Ebola outbreak in West Africa, primarily affecting Guinea, Sierra Leone, and Liberia, has exceeded all previous Ebola outbreaks in the number of cases and in international response. There have been 20 significant outbreaks of Ebola virus disease in Sub-Saharan Africa prior to the 2014 outbreak, the largest being that in Uganda in 2000, with 425 cases and a mortality of 53%. Since the first outbreaks in Sudan and Zaire in 1976, transmission within health facilities has been of major concern, affecting healthcare workers and acting as amplifiers of spread into the community. The lack of resources for infection control and personal protective equipment are the main reasons for nosocomial transmission. Local strategies to improve infection control, and a greater understanding of local community views on the disease, have helped to bring outbreaks under control. Recommendations from previous outbreaks include improved disease surveillance to enable more rapid health responses, the wider availability of personal protective equipment, and greater international preparedness.
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Affiliation(s)
- P Shears
- Wirral University Teaching Hospital, Wirral, Merseyside, UK.
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124
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Lo Iacono G, Cunningham AA, Fichet-Calvet E, Garry RF, Grant DS, Khan SH, Leach M, Moses LM, Schieffelin JS, Shaffer JG, Webb CT, Wood JLN. Using modelling to disentangle the relative contributions of zoonotic and anthroponotic transmission: the case of lassa fever. PLoS Negl Trop Dis 2015; 9:e3398. [PMID: 25569707 PMCID: PMC4288732 DOI: 10.1371/journal.pntd.0003398] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 11/07/2014] [Indexed: 12/22/2022] Open
Abstract
Background Zoonotic infections, which transmit from animals to humans, form the majority of new human pathogens. Following zoonotic transmission, the pathogen may already have, or may acquire, the ability to transmit from human to human. With infections such as Lassa fever (LF), an often fatal, rodent-borne, hemorrhagic fever common in areas of West Africa, rodent-to-rodent, rodent-to-human, human-to-human and even human-to-rodent transmission patterns are possible. Indeed, large hospital-related outbreaks have been reported. Estimating the proportion of transmission due to human-to-human routes and related patterns (e.g. existence of super-spreaders), in these scenarios is challenging, but essential for planned interventions. Methodology/Principal Findings Here, we make use of an innovative modeling approach to analyze data from published outbreaks and the number of LF hospitalized patients to Kenema Government Hospital in Sierra Leone to estimate the likely contribution of human-to-human transmission. The analyses show that almost of the cases at KGH are secondary cases arising from human-to-human transmission. However, we found much of this transmission is associated with a disproportionally large impact of a few individuals (‘super-spreaders’), as we found only of human cases result in an effective reproduction number (i.e. the average number of secondary cases per infectious case) , with a maximum value up to . Conclusions/Significance This work explains the discrepancy between the sizes of reported LF outbreaks and a clinical perception that human-to-human transmission is low. Future assessment of risks of LF and infection control guidelines should take into account the potentially large impact of super-spreaders in human-to-human transmission. Our work highlights several neglected topics in LF research, the occurrence and nature of super-spreading events and aspects of social behavior in transmission and detection. Many pathogens have the ability to infect different species. Lassa fever virus is an important example; this virus infects a species of rodent in West Africa, and can cause a severe disease in people. Lassa fever virus is transmitted from rodent-to-rodent, rodent-to-human, human-to-human and perhaps human-to-rodent. So far, the relative importance of these routes has not been assessed. Here we focus on the risk for humans; undoubtedly, most human infections are acquired by contact with rodents or their urine, but the relative risk of rodent-to-human and human-to-human transmission is unknown. We use mathematical modeling to address this. First, we identified Lassa fever outbreaks known to be due to human-to-human chains of transmission. Then, we looked at people hospitalized with the disease in Kenema Government Hospital, Sierra Leone (KGH), who could have been infected either by rodents or humans. We asked, what should the proportion of patients be who get infected by humans, assuming the statistical patterns observed in the human-to-human chains are the same in both instances? We found that around of patients with Lassa fever in KGH probably acquired the disease from another person. In addition, the patterns of disease in people suggest that these of cases are probably initiated by only a small number of infected people (who could be thought of as super-spreaders).
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Affiliation(s)
- Giovanni Lo Iacono
- Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
| | | | | | - Robert F. Garry
- Department of Microbiology and Immunology, Tulane University, New Orleans, Louisiana, United States of America
- Broad Institute, Cambridge, Massachusetts, United States of America
- Zalgen Labs, LLC, Germantown, Maryland, United States of America
| | - Donald S. Grant
- Lassa Fever Program, Kenema Government Hospital, Kenema, Sierra Leone
| | - Sheik Humarr Khan
- Lassa Fever Program, Kenema Government Hospital, Kenema, Sierra Leone
| | - Melissa Leach
- Institute of Development Studies, University of Sussex. Brighton, United Kingdom
| | - Lina M. Moses
- Department of Microbiology and Immunology, Tulane University, New Orleans, Louisiana, United States of America
| | - John S. Schieffelin
- Sections of Infectious Disease, Departments of Pediatrics and Internal Medicine, School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Jeffrey G. Shaffer
- Department of Biostatistics and Bioinformatics, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
| | - Colleen T. Webb
- Department of Biology, Colorado State University, Fort Collins, Colorado, United States of America
| | - James L. N. Wood
- Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Cambridge, United Kingdom
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Delayed inflammatory and cell death responses are associated with reduced pathogenicity in Lujo virus-infected cynomolgus macaques. J Virol 2014; 89:2543-52. [PMID: 25520505 DOI: 10.1128/jvi.02246-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED To identify host factors associated with arenavirus virulence, we used a cynomolgus macaque model to evaluate the pathogenesis of Lujo virus (LUJV), a recently emerged arenavirus that caused an outbreak of severe viral hemorrhagic fever in southern Africa. In contrast to human cases, LUJV caused mild, nonlethal illness in macaques. We then compared this to contrasting clinical outcomes during arenavirus infection, specifically to samples obtained from macaques infected with three highly pathogenic lines of Lassa virus (LASV), the causative agent of Lassa fever (LF). We assessed gene expression in peripheral blood mononuclear cells (PBMC) and determined genes that significantly changed expression relative to that in uninfected animals over the course of infection. We detected a 72-h delay in the induction of host responses to infection during LUJV infection compared to that of the animals infected with LASV. This included genes associated with inflammatory and antiviral responses and was particularly apparent among groups of genes promoting cell death. We also observed early differential expression of a subset of genes specific to LUJV infection that accounts for the delayed inflammatory response. Cell type enrichment analysis suggested that host response induction delay and an LUJV-specific profile are due to a different proportion of natural killer cells responding in LUJV infection than that in the LASV-infected animals. Together, these data indicate that delayed proinflammatory and proapoptotic host responses to arenavirus infection could ameliorate disease severity. This conclusion provides insight into the cellular and molecular mechanisms of arenaviral hemorrhagic fever and suggests potential strategies for therapeutic development. IMPORTANCE Old World arenaviruses are significant human pathogens that often are associated with high mortality. However, mechanisms underlying disease severity and virulence in arenavirus hemorrhagic fever are largely unknown, particularly regarding host responses that contribute to pathogenicity. This study describes a comparison between Lujo and Lassa virus infection in cynomolgus macaques. Lujo virus-infected macaques developed only mild illness, while Lassa virus-infected macaques developed severe illness consistent with Lassa fever. We determined that mild disease is associated with a delay in host expression of genes linked to virulence, such as those causing inflammation and cell death, and with distinct cell types that may mediate this delay. This is the first study to associate the timing and directionality of gene expression with arenaviral pathogenicity and disease outcome and evokes new potential approaches for developing effective therapeutics for treating these deadly emerging pathogens.
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Reynard S, Russier M, Fizet A, Carnec X, Baize S. Exonuclease domain of the Lassa virus nucleoprotein is critical to avoid RIG-I signaling and to inhibit the innate immune response. J Virol 2014; 88:13923-7. [PMID: 25253344 PMCID: PMC4248989 DOI: 10.1128/jvi.01923-14] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/15/2014] [Indexed: 11/20/2022] Open
Abstract
Lassa virus (LASV), which causes a viral hemorrhagic fever, inhibits the innate immune response. The exonuclease (ExoN) domain of its nucleoprotein (NP) is implicated in the suppression of retinoic acid-inducible gene I (RIG-I) signaling. We show here that a LASV in which ExoN function has been abolished strongly activates innate immunity and that this effect is dependent on RIG-I signaling. These results highlight the key role of NP ExoN function in the immune evasion that occurs during LASV infection.
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Affiliation(s)
- Stéphanie Reynard
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, Lyon, France; Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1, CNRS UMR5308, Lyon, France
| | - Marion Russier
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, Lyon, France; Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1, CNRS UMR5308, Lyon, France
| | - Alexandra Fizet
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, Lyon, France; Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1, CNRS UMR5308, Lyon, France
| | - Xavier Carnec
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, Lyon, France; Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1, CNRS UMR5308, Lyon, France
| | - Sylvain Baize
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, Lyon, France; Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1, CNRS UMR5308, Lyon, France
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Sewlall NH, Richards G, Duse A, Swanepoel R, Paweska J, Blumberg L, Dinh TH, Bausch D. Clinical features and patient management of Lujo hemorrhagic fever. PLoS Negl Trop Dis 2014; 8:e3233. [PMID: 25393244 PMCID: PMC4230886 DOI: 10.1371/journal.pntd.0003233] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 09/02/2014] [Indexed: 12/14/2022] Open
Abstract
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 options typically available in industrialized countries. METHODS AND FINDINGS We describe the clinical features of five cases of Lujo hemorrhagic fever and summarize their clinical management, as well as providing additional epidemiologic detail regarding the 2008 outbreak. Illness typically began with the abrupt onset of fever, malaise, headache, and myalgias followed successively by sore throat, chest pain, gastrointestinal symptoms, rash, minor hemorrhage, subconjunctival injection, and neck and facial swelling over the first week of illness. No major hemorrhage was noted. Neurological signs were sometimes seen in the late stages. Shock and multi-organ system failure, often with evidence of disseminated intravascular coagulopathy, ensued in the second week, with death in four of the five cases. Distinctive treatment components of the one surviving patient included rapid commencement of the antiviral drug ribavirin and administration of HMG-CoA reductase inhibitors (statins), N-acetylcysteine, and recombinant factor VIIa. CONCLUSIONS Lujo virus causes a clinical syndrome remarkably similar to Lassa fever. Considering the high case-fatality and significant logistical impediments to controlled treatment efficacy trials for viral hemorrhagic fever, it is both logical and ethical to explore the use of the various compounds used in the treatment of the surviving case reported here in future outbreaks. Clinical observations should be systematically recorded to facilitate objective evaluation of treatment efficacy. Due to the risk of secondary transmission, viral hemorrhagic fever precautions should be implemented for all cases of Lujo virus infection, with specialized precautions to protect against aerosols when performing enhanced-risk procedures such as endotracheal intubation.
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Affiliation(s)
- Nivesh H. Sewlall
- Internal Medicine, Morningside MediClinic, Johannesburg, South Africa
- Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa
- * E-mail:
| | - Guy Richards
- Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa
| | - Adriano Duse
- Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa
| | - Robert Swanepoel
- Department of Medicine, University of Pretoria, Pretoria, South Africa
| | - Janusz Paweska
- National Institute of Communicable Disease, Sandringham, South Africa
| | - Lucille Blumberg
- National Institute of Communicable Disease, Sandringham, South Africa
| | - Thu Ha Dinh
- Centers for Disease control and Prevention, Atlanta, Georgia, United States of America
| | - Daniel Bausch
- Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
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128
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Smith DR, Holbrook MR, Gowen BB. Animal models of viral hemorrhagic fever. Antiviral Res 2014; 112:59-79. [PMID: 25448088 DOI: 10.1016/j.antiviral.2014.10.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/24/2014] [Accepted: 10/05/2014] [Indexed: 12/13/2022]
Abstract
The term "viral hemorrhagic fever" (VHF) designates a syndrome of acute febrile illness, increased vascular permeability and coagulation defects which often progresses to bleeding and shock and may be fatal in a significant percentage of cases. The causative agents are some 20 different RNA viruses in the families Arenaviridae, Bunyaviridae, Filoviridae and Flaviviridae, which are maintained in a variety of animal species and are transferred to humans through direct or indirect contact or by an arthropod vector. Except for dengue, which is transmitted among humans by mosquitoes, the geographic distribution of each type of VHF is determined by the range of its animal reservoir. Treatments are available for Argentine HF and Lassa fever, but no approved countermeasures have been developed against other types of VHF. The development of effective interventions is hindered by the sporadic nature of most infections and their occurrence in geographic regions with limited medical resources. Laboratory animal models that faithfully reproduce human disease are therefore essential for the evaluation of potential vaccines and therapeutics. The goal of this review is to highlight the current status of animal models that can be used to study the pathogenesis of VHF and test new countermeasures.
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Affiliation(s)
- Darci R Smith
- Southern Research Institute, Frederick, MD 21701, United States.
| | - Michael R Holbrook
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, United States
| | - Brian B Gowen
- Institute for Antiviral Research and Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT 84322, United States
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129
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The rubber plantation environment and Lassa fever epidemics in Liberia, 2008–2012: A spatial regression. Spat Spatiotemporal Epidemiol 2014; 11:163-74. [DOI: 10.1016/j.sste.2014.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 03/12/2014] [Accepted: 04/30/2014] [Indexed: 11/19/2022]
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130
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Peterson AT, Moses LM, Bausch DG. Mapping transmission risk of Lassa fever in West Africa: the importance of quality control, sampling bias, and error weighting. PLoS One 2014; 9:e100711. [PMID: 25105746 PMCID: PMC4126660 DOI: 10.1371/journal.pone.0100711] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 05/13/2014] [Indexed: 12/15/2022] Open
Abstract
Lassa fever is a disease that has been reported from sites across West Africa; it is caused by an arenavirus that is hosted by the rodent M. natalensis. Although it is confined to West Africa, and has been documented in detail in some well-studied areas, the details of the distribution of risk of Lassa virus infection remain poorly known at the level of the broader region. In this paper, we explored the effects of certainty of diagnosis, oversampling in well-studied region, and error balance on results of mapping exercises. Each of the three factors assessed in this study had clear and consistent influences on model results, overestimating risk in southern, humid zones in West Africa, and underestimating risk in drier and more northern areas. The final, adjusted risk map indicates broad risk areas across much of West Africa. Although risk maps are increasingly easy to develop from disease occurrence data and raster data sets summarizing aspects of environments and landscapes, this process is highly sensitive to issues of data quality, sampling design, and design of analysis, with macrogeographic implications of each of these issues and the potential for misrepresenting real patterns of risk.
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Affiliation(s)
- A. Townsend Peterson
- Biodiversity Institute, University of Kansas, Lawrence, Kansas, United States of America
- * E-mail:
| | - Lina M. Moses
- Department of Tropical Medicine, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
| | - Daniel G. Bausch
- Department of Tropical Medicine, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
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131
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Inhibition of arenavirus infection by a glycoprotein-derived peptide with a novel mechanism. J Virol 2014; 88:8556-64. [PMID: 24850726 DOI: 10.1128/jvi.01133-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The family Arenaviridae includes a number of viruses of public health importance, such as the category A hemorrhagic fever viruses Lassa virus, Junin virus, Machupo virus, Guanarito virus, and Sabia virus. Current chemotherapy for arenavirus infection is limited to the nucleoside analogue ribavirin, which is characterized by considerable toxicity and treatment failure. Using Pichinde virus as a model arenavirus, we attempted to design glycoprotein-derived fusion inhibitors similar to the FDA-approved anti-HIV peptide enfuvirtide. We have identified a GP2-derived peptide, AVP-p, with antiviral activity and no acute cytotoxicity. The 50% inhibitory dose (IC50) for the peptide is 7 μM, with complete inhibition of viral plaque formation at approximately 20 μM, and its antiviral activity is largely sequence dependent. AVP-p demonstrates activity against viruses with the Old and New World arenavirus viral glycoprotein complex but not against enveloped viruses of other families. Unexpectedly, fusion assays reveal that the peptide induces virus-liposome fusion at neutral pH and that the process is strictly glycoprotein mediated. As observed in cryo-electron micrographs, AVP-p treatment causes morphological changes consistent with fusion protein activation in virions, including the disappearance of prefusion glycoprotein spikes and increased particle diameters, and fluorescence microscopy shows reduced binding by peptide-treated virus. Steady-state fluorescence anisotropy measurements suggest that glycoproteins are destabilized by peptide-induced alterations in viral membrane order. We conclude that untimely deployment of fusion machinery by the peptide could render virions less able to engage in on-pathway receptor binding or endosomal fusion. AVP-p may represent a potent, highly specific, novel therapeutic strategy for arenavirus infection. IMPORTANCE Because the only drug available to combat infection by Lassa virus, a highly pathogenic arenavirus, is toxic and prone to treatment failure, we identified a peptide, AVP-p, derived from the fusion glycoprotein of a nonpathogenic model arenavirus, which demonstrates antiviral activity and no acute cytotoxicity. AVP-p is unique among self-derived inhibitory peptides in that it shows broad, specific activity against pseudoviruses bearing Old and New World arenavirus glycoproteins but not against viruses from other families. Further, the peptide's mechanism of action is highly novel. Biochemical assays and cryo-electron microscopy indicate that AVP-p induces premature activation of viral fusion proteins through membrane perturbance. Peptide treatment, however, does not increase the infectivity of cell-bound virus. We hypothesize that prematurely activated virions are less fit for receptor binding and membrane fusion and that AVP-p may represent a viable therapeutic strategy for arenavirus infection.
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132
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Abstract
BACKGROUND Lassa fever (LF), an often-fatal hemorrhagic disease caused by Lassa virus (LASV), is a major public health threat in West Africa. When the violent civil conflict in Sierra Leone (1991 to 2002) ended, an international consortium assisted in restoration of the LF program at Kenema Government Hospital (KGH) in an area with the world's highest incidence of the disease. METHODOLOGY/PRINCIPAL FINDINGS Clinical and laboratory records of patients presenting to the KGH Lassa Ward in the post-conflict period were organized electronically. Recombinant antigen-based LF immunoassays were used to assess LASV antigenemia and LASV-specific antibodies in patients who met criteria for suspected LF. KGH has been reestablished as a center for LF treatment and research, with over 500 suspected cases now presenting yearly. Higher case fatality rates (CFRs) in LF patients were observed compared to studies conducted prior to the civil conflict. Different criteria for defining LF stages and differences in sensitivity of assays likely account for these differences. The highest incidence of LF in Sierra Leone was observed during the dry season. LF cases were observed in ten of Sierra Leone's thirteen districts, with numerous cases from outside the traditional endemic zone. Deaths in patients presenting with LASV antigenemia were skewed towards individuals less than 29 years of age. Women self-reporting as pregnant were significantly overrepresented among LASV antigenemic patients. The CFR of ribavirin-treated patients presenting early in acute infection was lower than in untreated subjects. CONCLUSIONS/SIGNIFICANCE Lassa fever remains a major public health threat in Sierra Leone. Outreach activities should expand because LF may be more widespread in Sierra Leone than previously recognized. Enhanced case finding to ensure rapid diagnosis and treatment is imperative to reduce mortality. Even with ribavirin treatment, there was a high rate of fatalities underscoring the need to develop more effective and/or supplemental treatments for LF.
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133
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Grant DS, Khan H, Schieffelin J, Bausch DG. Lassa Fever. Emerg Infect Dis 2014. [DOI: 10.1016/b978-0-12-416975-3.00004-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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134
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Abstract
The attenuated Lassa vaccine candidate ML29 is a laboratory-produced reassortant between Lassa and Mopeia viruses, two Old World arenaviruses that differ by 40% in nucleic acid sequence. In our previous studies, ML29 elicited sterilizing immunity against Lassa virus challenge in guinea pigs and marmosets and virus-specific cell-mediated immunity in both simian immunodeficiency virus (SIV)-infected and uninfected rhesus macaques. Here, we show that ML29 is stable after 12 passages in vitro without losing its plaque morphology or its attenuated phenotype in suckling mice. Additionally, we used deep sequencing to characterize the viral population comprising the original stock of ML29, the stock of ML29 after 12 passages in Vero cells, and the ML29 isolates obtained from vaccinated animals. Twenty-seven isolates bore approximately 77 mutations that exceeded 20% of the single-nucleotide polymorphism (SNP) changes at any single locus. Of these 77 mutations, 5 appeared to be host specific, for example, appearing in mice but not in primates. None of these mutations were reversions of ML29 to the sequences of the parental Lassa and Mopeia viruses. The host-specific mutations indicate viral adaptations to virus-host interactions, and such interactions make reasonable targets for antiviral approaches. Variants capable of chronic infection did not emerge from any of the primate infections, even in immune-deficient animals, indicating that the ML29 reassortant is reasonably stable in vivo. In conclusion, the preclinical studies of ML29 as a Lassa virus vaccine candidate have been advanced, showing high levels of protection in nonhuman primates and acceptable stability both in vitro and in vivo.
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135
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Safronetz D, Sogoba N, Lopez JE, Maiga O, Dahlstrom E, Zivcec M, Feldmann F, Haddock E, Fischer RJ, Anderson JM, Munster VJ, Branco L, Garry R, Porcella SF, Schwan TG, Feldmann H. Geographic distribution and genetic characterization of Lassa virus in sub-Saharan Mali. PLoS Negl Trop Dis 2013; 7:e2582. [PMID: 24340119 PMCID: PMC3855028 DOI: 10.1371/journal.pntd.0002582] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/28/2013] [Indexed: 01/13/2023] Open
Abstract
Background Lassa fever is an acute viral illness characterized by multi-organ failure and hemorrhagic manifestations. Lassa fever is most frequently diagnosed in Nigeria, Sierra Leone, Liberia, and Guinea, although sporadic cases have been recorded in other West African countries, including Mali. The etiological agent of Lassa fever is Lassa virus (LASV), an Arenavirus which is maintained in nature and frequently transmitted to humans by Mastomys natalensis. The purpose of this study was to better define the geographic distribution of LASV-infected rodents in sub-Saharan Mali. Methodologies/Principal Findings Small mammals were live-trapped at various locations across Mali for the purpose of identifying potential zoonotic pathogens. Serological and molecular assays were employed and determined LASV infected rodents were exclusively found in the southern Mali near the border of Côte d'Ivoire. Overall, 19.4% of Mastomys natalensis sampled in this region had evidence of LASV infection, with prevalence rates for individual villages ranging from 0 to 52%. Full-length genomic sequences were determined using high throughput sequencing methodologies for LASV isolates generated from tissue samples of rodents collected in four villages and confirmed the phylogenetic clustering of Malian LASV with strain AV. Conclusions/Significance The risk of human infections with LASV is greatest in villages in southern Mali. Lassa fever should be considered in the differential diagnosis for febrile individuals and appropriate diagnostic techniques need to be established to determine the incidence of infection and disease in these regions. Lassa fever is an acute infection associated with hemorrhagic manifestations and multi-organ failure in West Africa. The etiological agent of Lassa fever is Lassa virus (LASV), a rodent-borne arenavirus, which is maintained in nature and transmitted to humans by the multimammate rat, Mastomys natalensis. Despite the ubiquitous nature of the rodent reservoir, LASV-infected animals are most commonly documented in Nigeria, Sierra Leone, Guinea and Liberia. These four countries represent the historic endemic region for Lassa fever, although there is increasing evidence of sporadic cases occurring in other West African nations including Mali. To better define the geographic distribution of LASV-infected rodents in Mali, we tested samples from small animals collected at 27 sites across the country. Although M. natalensis was the predominant rodent species in the majority of villages, evidence of LASV infection was exclusively found in southern Mali, where overall nearly 20% of rodents were positive. The full genomic sequence was determined for five isolates and confirmed LASV in Mali is closely related to strain AV. We conclude that there is a risk of human exposure to LASV in villages in southern Mali and Lassa fever should be considered in the differential diagnosis for acutely ill, febrile patients.
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Affiliation(s)
- David Safronetz
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail: (DS); (HF)
| | - Nafomon Sogoba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Job E. Lopez
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Ousmane Maiga
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Eric Dahlstrom
- Rocky Mountain Laboratory Research Technologies Section, Genomics Unit, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Marko Zivcec
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Friederike Feldmann
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Elaine Haddock
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert J. Fischer
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Jennifer M. Anderson
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Vincent J. Munster
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Luis Branco
- Department of Microbiology and Immunology, Tulane School of Medicine, New Orleans, Louisiana, United States of America
- Autoimmune Technologies LLC, New Orleans, Louisiana, United States of America
| | - Robert Garry
- Department of Microbiology and Immunology, Tulane School of Medicine, New Orleans, Louisiana, United States of America
| | - Stephen F. Porcella
- Rocky Mountain Laboratory Research Technologies Section, Genomics Unit, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Tom G. Schwan
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Heinz Feldmann
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail: (DS); (HF)
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136
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Healthcare-associated infections in sub-Saharan Africa. J Hosp Infect 2013; 85:257-67. [DOI: 10.1016/j.jhin.2013.09.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 09/01/2013] [Indexed: 11/18/2022]
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137
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Ajayi NA, Nwigwe CG, Azuogu BN, Onyire BN, Nwonwu EU, Ogbonnaya LU, Onwe FI, Ekaete T, Günther S, Ukwaja KN. Containing a Lassa fever epidemic in a resource-limited setting: outbreak description and lessons learned from Abakaliki, Nigeria (January–March 2012). Int J Infect Dis 2013; 17:e1011-6. [DOI: 10.1016/j.ijid.2013.05.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 05/28/2013] [Accepted: 05/30/2013] [Indexed: 01/25/2023] Open
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138
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Abstract
Access to critical care is rapidly growing in areas of the world where it was previously nonexistent and where infectious diseases often comprise the largest disease burden. Additionally, with crowding, mass migrations, and air travel, infectious diseases previously geographically confined are quickly spread across the planet, often in shorter time frames than disease incubation periods. Hence, critical care practitioners must be familiar with infectious diseases previously confined to the developing world. This article reviews selected tropical diseases that are seen in diverse locales and often require critical care services.
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Affiliation(s)
- Srinivas Murthy
- Department of Critical Care Medicine, Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
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139
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Sogoba N, Feldmann H, Safronetz D. Lassa fever in West Africa: evidence for an expanded region of endemicity. Zoonoses Public Health 2013; 59 Suppl 2:43-7. [PMID: 22958249 DOI: 10.1111/j.1863-2378.2012.01469.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Lassa virus (LASV) is endemic in Sierra Leone, Guinea and Liberia (known as the Mano River region) and Nigeria and Lassa fever cases from these countries are being reported annually. Recent investigations have found evidence for an expanded endemicity zone between the two known Lassa endemic regions indicating that LASV is more widely distributed throughout the Tropical Wooded Savanna ecozone in West Africa.
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Affiliation(s)
- N Sogoba
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
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140
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Infection of type I interferon receptor-deficient mice with various old world arenaviruses: a model for studying virulence and host species barriers. PLoS One 2013; 8:e72290. [PMID: 23991083 PMCID: PMC3750052 DOI: 10.1371/journal.pone.0072290] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 07/13/2013] [Indexed: 11/26/2022] Open
Abstract
Lassa virus causes hemorrhagic Lassa fever in humans, while the related Old World arenaviruses Mopeia, Morogoro, and Mobala are supposedly apathogenic to humans and cause only inapparent infection in non-human primates. Here, we studied whether the virulence of Old World arenaviruses in humans and non-human primates is reflected in type I interferon receptor deficient (IFNAR-/-) mice by testing several strains of Lassa virus vs. the apathogenic viruses Mopeia, Morogoro, and Mobala. All Lassa virus strains tested—Josiah, AV, BA366, and Nig04-10—replicated to high titers in blood, lung, kidney, heart, spleen, brain, and liver and caused disease as evidenced by weight loss and elevation of aspartate and alanine aminotransferase (AST and ALT) levels with a high AST/ALT ratio. Lassa fever-like pathology included acute hepatitis, interstitial pneumonia, and pronounced disturbance of splenic cytoarchitecture. Infiltrations of activated monocytes/macrophages expressing inducible nitric oxide synthase and T cells were found in liver and lung. In contrast, Mopeia, Morogoro, and Mobala virus replicated poorly in the animals and acute inflammatory alterations were not noted. Depletion of CD4+ and CD8+ T cells strongly enhanced susceptibility of IFNAR-/- mice to the apathogenic viruses. In conclusion, the virulence of Old World arenaviruses in IFNAR-/- mice correlates with their virulence in humans and non-human primates. In addition to the type I interferon system, T cells seem to regulate whether or not an arenavirus can productively infect non-host rodent species. The observation that Lassa virus overcomes the species barrier without artificial depletion of T cells suggests it is able to impair T cell functionality in a way that corresponds to depletion.
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141
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Mice lacking functional STAT1 are highly susceptible to lethal infection with Lassa virus. J Virol 2013; 87:10908-11. [PMID: 23903830 DOI: 10.1128/jvi.01433-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lassa fever (LF) is a potentially lethal human disease that is caused by the arenavirus Lassa virus (LASV). Annually, around 300,000 infections with up to 10,000 deaths occur in regions of Lassa fever endemicity in West Africa. Here we demonstrate that mice lacking a functional STAT1 pathway are highly susceptible to infection with LASV and develop lethal disease with pathology similar to that reported in humans.
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142
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Ibekwe TS, Nwegbu MM, Asogun D, Adomeh DI, Okokhere PO. The sensitivity and specificity of Lassa virus IgM by ELISA as screening tool at early phase of Lassa fever infection. Niger Med J 2013; 53:196-9. [PMID: 23661877 PMCID: PMC3640238 DOI: 10.4103/0300-1652.107552] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background: Early diagnosis, prompt treatment, and disease containment are vital measures in the management of Lassa fever (LF), a lethal and contagious arenaviral hemorrhagic disease prevalent in West Africa. Lassa Virus (LAV)-specific Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) test, the gold standard for diagnosis, is unavailable in most centers. Serologic detection of LAV IgM is a more accessible tool and this work was to investigate its adequacy as an early marker for LF. Patients and Methods: A prospective case–control study conducted July 2007-March 2011 in a tertiary referral health center in Nigeria. Blood samples for test and control were evaluated for Lassa specific antigens and IgM using RT-PCR (primers S36+ and LVS 339) and indirect ELISA (Lassa Nucleo-protein (NP)-Antigen) respectively. RT-PCR outcome was used as standard to test for the sensitivity and specificity of IgM. Results: Of the 37 confirmed cases of LF infection by RT-PCR, 21 (57%) were IgM positive. Amongst the 35 confirmed negative cases (control group), eight were IgM positive. The diagnostic sensitivity and specificity of the IgM assay were 57% and 77% respectively. The negative and positive predictive values of the IgM serological assay were 63% and 72%, respectively, while the efficiency of the test was 67%. Conclusion: The specificity and sensitivity of IgM as a screening tool for early detection of LF appear weak and, hence, the need for a reliable LF “rapid screening kit” since RT-PCR is unavailable in most centers. In the interim, “high clinical index of suspicion,” irrespective of IgM status, requires urgent referral to confirmatory centers.
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Affiliation(s)
- Titus S Ibekwe
- The Research Unit, Lassa Fever Research and Diagnostic Centre, Irrua Specialist Teaching Hospital, Irrua, Nigeria ; Department of Ear, Nose, and Throat, College of Health Sciences, University of Abuja, Nigeria
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143
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Malhotra S, Yen JY, Honko AN, Garamszegi S, Caballero IS, Johnson JC, Mucker EM, Trefry JC, Hensley LE, Connor JH. Transcriptional profiling of the circulating immune response to lassa virus in an aerosol model of exposure. PLoS Negl Trop Dis 2013; 7:e2171. [PMID: 23638192 PMCID: PMC3636129 DOI: 10.1371/journal.pntd.0002171] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 03/06/2013] [Indexed: 11/22/2022] Open
Abstract
Lassa virus (LASV) is a significant human pathogen that is endemic to several countries in West Africa. Infection with LASV leads to the development of hemorrhagic fever in a significant number of cases, and it is estimated that thousands die each year from the disease. Little is known about the complex immune mechanisms governing the response to LASV or the genetic determinants of susceptibility and resistance to infection. In the study presented here, we have used a whole-genome, microarray-based approach to determine the temporal host response in the peripheral blood mononuclear cells (PBMCs) of non-human primates (NHP) following aerosol exposure to LASV. Sequential sampling over the entire disease course showed that there are strong transcriptional changes of the immune response to LASV exposure, including the early induction of interferon-responsive genes and Toll-like receptor signaling pathways. However, this increase in early innate responses was coupled with a lack of pro-inflammatory cytokine response in LASV exposed NHPs. There was a distinct lack of cytokines such as IL1β and IL23α, while immunosuppressive cytokines such as IL27 and IL6 were upregulated. Comparison of IRF/STAT1-stimulated gene expression with the viral load in LASV exposed NHPs suggests that mRNA expression significantly precedes viremia, and thus might be used for early diagnostics of the disease. Our results provide a transcriptomic survey of the circulating immune response to hemorrhagic LASV exposure and provide a foundation for biomarker identification to allow clinical diagnosis of LASV infection through analysis of the host response. Lassa virus (LASV), a member of the Arenaviridae family, is a viral hemorrhagic fever causing virus endemic to several countries in West Africa with a history of sporadic importation into the United States. It has been characterized as a Category A agent, and despite the significant public health issues posed by LASV and the potential biodefense risks, little is known about the immune response to the virus. In the study presented here, we have taken an unbiased genomics approach to map the temporal host response in the peripheral blood mononuclear cells (PBMCs) of non-human primates (NHP) exposed to LASV. Gene expression patterns over the entire disease course showed that there are strong transcriptional changes of the immune response to LASV exposure, including the upregulation of Toll-like receptor signaling pathways and innate antiviral transcription factors. However, there was a lack of pro-inflammatory cytokine response in LASV exposed NHPs similar to what is seen in human disease. Our data suggests that LASV induces negative regulation of immunological events, leading to an inefficient adaptive immune response as observed in LASV-infected human patients. Our results provide a picture of the host's circulating immune response to hemorrhagic LASV exposure and demonstrate that gene expression patterns correlate with specific stages of disease progression.
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Affiliation(s)
- Shikha Malhotra
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Judy Y. Yen
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Anna N. Honko
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Sara Garamszegi
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Bioinformatics, Boston University, Boston, Massachusetts, United States of America
| | - Ignacio S. Caballero
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Bioinformatics, Boston University, Boston, Massachusetts, United States of America
| | - Joshua C. Johnson
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Eric M. Mucker
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - John C. Trefry
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Lisa E. Hensley
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - John H. Connor
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Bioinformatics, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
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144
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Dongo AE, Kesieme EB, Iyamu CE, Okokhere PO, Akhuemokhan OC, Akpede GO. Lassa fever presenting as acute abdomen: a case series. Virol J 2013; 10:123. [PMID: 23597024 PMCID: PMC3639802 DOI: 10.1186/1743-422x-10-123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 04/08/2013] [Indexed: 11/10/2022] Open
Abstract
Lassa fever, an endemic zoonotic viral infection in West Africa, presents with varied symptoms including fever, vomiting, retrosternal pain, abdominal pain, sore-throat, mucosal bleeding, seizures and coma. When fever and abdominal pain are the main presenting symptoms, and a diagnosis of acute abdomen is entertained, Lassa fever is rarely considered in the differential diagnosis, even in endemic areas. Rather the diagnosis of Lassa fever is suspected only after surgical intervention. Therefore, such patients often undergo unnecessary surgery with resultant delay in the commencement of ribavirin therapy. This increases morbidity and mortality and the risk of nosocomial transmission to hospital staff. We report 7 patients aged between 17 months and 40 years who had operative intervention for suspected appendicitis, perforated typhoid ileitis, intussuception and ruptured ectopic pregnancy after routine investigations. All seven were post-operatively confirmed as Lassa fever cases. Four patients died postoperatively, most before commencement of ribavirin, while the other three patients eventually recovered with appropriate antibiotic treatment including intravenous ribavirin. Surgeons working in West Africa should include Lassa fever in the differential diagnosis of acute abdomen, especially appendicitis. The presence of high grade fever, proteinuria and thrombocytopenia in patients with acute abdomen should heighten the suspicion of Lassa fever. Prolonged intra-operative bleeding should not only raise suspicion of the disease but also serve to initiate precautions to prevent nosocomial transmission.
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Affiliation(s)
- Andrew E Dongo
- Department of Surgery, Irrua Specialist Teaching Hospital, PMB 08, Irrua, Edo State, Nigeria.
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145
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Zapata JC, Poonia B, Bryant J, Davis H, Ateh E, George L, Crasta O, Zhang Y, Slezak T, Jaing C, Pauza CD, Goicochea M, Moshkoff D, Lukashevich IS, Salvato MS. An attenuated Lassa vaccine in SIV-infected rhesus macaques does not persist or cause arenavirus disease but does elicit Lassa virus-specific immunity. Virol J 2013; 10:52. [PMID: 23402317 PMCID: PMC3602176 DOI: 10.1186/1743-422x-10-52] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 01/28/2013] [Indexed: 12/20/2022] Open
Abstract
Background Lassa hemorrhagic fever (LHF) is a rodent-borne viral disease that can be fatal for human beings. In this study, an attenuated Lassa vaccine candidate, ML29, was tested in SIV-infected rhesus macaques for its ability to elicit immune responses without instigating signs pathognomonic for arenavirus disease. ML29 is a reassortant between Lassa and Mopeia viruses that causes a transient infection in non-human primates and confers sterilizing protection from lethal Lassa viral challenge. However, since the LHF endemic area of West Africa also has high HIV seroprevalence, it is important to determine whether vaccination could be safe in the context of HIV infection. Results SIV-infected and uninfected rhesus macaques were vaccinated with the ML29 virus and monitored for specific humoral and cellular immune responses, as well as for classical and non-classical signs of arenavirus disease. Classical disease signs included viremia, rash, respiratory distress, malaise, high liver enzyme levels, and virus invasion of the central nervous system. Non-classical signs, derived from profiling the blood transcriptome of virulent and non-virulent arenavirus infections, included increased expression of interferon-stimulated genes (ISG) and decreased expression of COX2, IL-1β, coagulation intermediates and nuclear receptors needed for stress signaling. All vaccinated monkeys showed ML29-specific antibody responses and ML29-specific cell-mediated immunity. Conclusion SIV-infected and uninfected rhesus macaques responded similarly to ML29 vaccination, and none developed chronic arenavirus infection. Importantly, none of the macaques developed signs, classical or non-classical, of arenavirus disease.
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Affiliation(s)
- Juan C Zapata
- Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
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146
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Ftika L, Maltezou HC. Viral haemorrhagic fevers in healthcare settings. J Hosp Infect 2013; 83:185-92. [PMID: 23333147 DOI: 10.1016/j.jhin.2012.10.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 10/02/2012] [Indexed: 01/20/2023]
Abstract
Viral haemorrhagic fevers (VHFs) typically manifest as rapidly progressing acute febrile syndromes with profound haemorrhagic manifestations and very high fatality rates. VHFs that have the potential for human-to-human transmission and onset of large nosocomial outbreaks include Crimean-Congo haemorrhagic fever, Ebola haemorrhagic fever, Marburg haemorrhagic fever and Lassa fever. Nosocomial outbreaks of VHFs are increasingly reported nowadays, which likely reflects the dynamics of emergence of VHFs. Such outbreaks are associated with an enormous impact in terms of human lives and costs for the management of cases, contact tracing and containment. Surveillance, diagnostic capacity, infection control and the overall preparedness level for management of a hospital-based VHF event are very limited in most endemic countries. Diagnostic capacities for VHFs should increase in the field and become affordable. Availability of appropriate protective equipment and education of healthcare workers about safe clinical practices and infection control is the mainstay for the prevention of nosocomial spread of VHFs.
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Affiliation(s)
- L Ftika
- Department for Interventions in Healthcare Facilities, Hellenic Centre for Disease Control and Prevention, Athens, Greece
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147
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Safronetz D, Strong JE, Feldmann F, Haddock E, Sogoba N, Brining D, Geisbert TW, Scott DP, Feldmann H. A recently isolated Lassa virus from Mali demonstrates atypical clinical disease manifestations and decreased virulence in cynomolgus macaques. J Infect Dis 2013; 207:1316-27. [PMID: 23303805 DOI: 10.1093/infdis/jit004] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The virulence of Soromba-R, a Lassa virus strain recently isolated from southern Mali, was assessed in 2 animal models of Lassa fever: inbred strain 13 guinea pigs and cynomolgus macaques. In both models, the Malian isolate demonstrated tissue tropism and viral titers similar to those of historical Lassa virus isolates from Sierra Leone (Josiah) and Liberia (Z-132); however, the Soromba-R isolate was found to be less pathogenic, as determined by decreased mortality and prolonged time to euthanasia in macaques. Interestingly, in addition to the classic indicators of Lassa fever, Soromba-R infection presented with moderate to severe pulmonary manifestations in the macaque model. Analysis of host responses demonstrated increased immune activation in Soromba-R-infected macaques, particularly in neutrophil-activating or -potentiating proinflammatory cytokines or growth factors, including tumor necrosis factor α, macrophage inflammatory protein 1α, interleukin 1β, and granulocyte colony-stimulating factor, as well as interleukin 5, which may be responsible for the decreased lethality and uncharacteristic clinical presentation. These results suggest that the strain of Lassa virus circulating in Mali might be less pathogenic than strains circulating in the historical region of endemicity and may result in an atypical presentation for Lassa fever, which could complicate clinical diagnosis.
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Affiliation(s)
- David Safronetz
- Laboratory of Virology, Division of Intramural Research, NationalInstitute of Allergy and Infectious Diseases/National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, USA
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148
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Gire SK, Stremlau M, Andersen KG, Schaffner SF, Bjornson Z, Rubins K, Hensley L, McCormick JB, Lander ES, Garry RF, Happi C, Sabeti PC. Epidemiology. Emerging disease or diagnosis? Science 2012; 338:750-2. [PMID: 23139320 DOI: 10.1126/science.1225893] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Stephen K Gire
- Center for Systems Biology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
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Abstract
Arenaviruses are a family of enveloped negative-stranded RNA viruses that can cause severe human disease ranging from encephalitis symptoms to fulminant hemorrhagic fever. The bi‑segmented RNA genome encodes four polypeptides: the nucleoprotein NP, the surface glycoprotein GP, the polymerase L, and the RING finger protein Z. Although it is the smallest arenavirus protein with a length of 90 to 99 amino acids and a molecular weight of approx. 11 kDa, the Z protein has multiple functions in the viral life cycle including (i) regulation of viral RNA synthesis, (ii) orchestration of viral assembly and budding, (iii) interaction with host cell proteins, and (iv) interferon antagonism. In this review, we summarize our current understanding of the structural and functional role of the Z protein in the arenavirus replication cycle.
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Affiliation(s)
- Sarah Katharina Fehling
- Institut für Virologie der Philipps-Universität Marburg, Hans-Meerwein-Str. 2, 35043 Marburg, Germany.
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Abstract
Lassa fever is a hemorrhagic fever endemic to West Africa and caused by Lassa virus, an Old World arenavirus. It may be fatal, but most patients recover from acute disease and some experience asymptomatic infection. The immune mechanisms associated with these different outcomes have not yet been fully elucidated, but considerable progress has recently been made, through the use of in vitro human models and nonhuman primates, the only relevant animal model that mimics the pathophysiology and immune responses induced in patients. We discuss here the roles of the various components of the innate and adaptive immune systems in Lassa virus infection and in the control of viral replication and pathogenesis.
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Affiliation(s)
- Marion Russier
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, 21 avenue Tony Garnier, 69365 Lyon, France;
| | - Delphine Pannetier
- Laboratoire P4 Jean Mérieux-Inserm, 21 avenue Tony Garnier, 69365 Lyon, France;
| | - Sylvain Baize
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, 21 avenue Tony Garnier, 69365 Lyon, France;
- Author to whom correspondence should be addressed; ; Tel.: +33-4-3728-2440; Fax: +33-4-3728-2441
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