ABSTRACT
BACKGROUND: During the five decades since their discovery, filoviruses of four species have caused human hemorrhagic fever outbreaks: Marburg (MARV) marburgvirus, and Zaire (EBOV), Sudan (SUDV) and Bundybugyo (BDBV) ebolaviruses. The largest, devastating EBOV epidemic in West Africa in 2014-16, has been followed by outbreaks of MARV in Uganda, 2017, and EBOV in Democratic Republic of Congo, 2018, emphasizing the need to develop preparedness to diagnose all filoviruses. OBJECTIVES: The aim of this study was to optimize a new filovirus RT-qPCR to detect all filoviruses, define its limits of detection (LOD) and perform a field evaluation with outbreak samples. STUDY DESIGN: A pan-filovirus RT-qPCR targeting the L gene was developed and evaluated within the EbolaMoDRAD (Ebola virus: modern approaches for developing bedside rapid diagnostics) project. Specificity and sensitivity were determined and the effect of inactivation and PCR reagents (liquid and lyophilized format) were tested. RESULTS: The LODs for the lyophilized pan-filovirus L-RT-qPCR assay were 9.4 copies per PCR reaction for EBOV, 9.9 for MARV, 1151 for SUDV, 65 for BDBV and 289 for Taï Forest virus. The test was set at the Pasteur Institute, Dakar, Senegal, and 83 Ebola patient samples, with viral load ranging from 5 to 5 million copies of EBOV per reaction, were screened. The results for the patient samples were in 100% concordance with the reference EBOV-specific assay. DISCUSSION: Overall, the assay showed good sensitivity and specificity, covered all filoviruses known to be human pathogens, performed well both in lyophilized and liquid-phase formats and with EBOV outbreak clinical samples.
Subject(s)
Filoviridae Infections/diagnosis , Real-Time Polymerase Chain Reaction/methods , Viral Proteins/genetics , Animals , Ebolavirus , Filoviridae , Filoviridae Infections/virology , Freeze Drying , Hemorrhagic Fever, Ebola/diagnosis , Hemorrhagic Fever, Ebola/virology , Humans , Limit of Detection , Marburg Virus Disease/diagnosis , Marburg Virus Disease/virology , Marburgvirus , Sensitivity and SpecificityABSTRACT
Tools with predictive capabilities in regards of filovirus outbreaks are mainly anthropocentric and have disregarded the ecological dimension of the problem. Here we contribute to shift the current paradigm by studying the dynamics of the putative main zoonotic niche of filoviruses, bats, and its link to environmental drivers. We propose a framework that combines data analysis, modeling, and the evaluation of sources of variability. We implement a regression analysis using factual data to correlate environmental parameters and the presence of bats to find the distribution of resources. The information inferred by the regression is fed into a compartmental model that describes the infection state. We also account for the lack of knowledge of some parameters using a sampling/averaging technique. As a result we estimate the spatio-temporal densities of bats. Importantly, we show that our approach is able to predict where and when an outbreak is likely to appear when tested against recent epidemic data in the context of Ebola. Our framework highlights the importance of considering the feedback between the ecology and the environment in zoonotic models and sheds light on the mechanisms to propagate filoviruses geographically. We expect that our methodology can help to design prevention policies and be used as a predictive tool in the context of zoonotic diseases associated to filoviruses.
Subject(s)
Chiroptera , Filoviridae Infections/epidemiology , Forecasting , Animals , Demography , Disease Outbreaks/statistics & numerical data , Disease Outbreaks/veterinary , Ebolavirus/isolation & purification , Ecology , Epidemics , Filoviridae Infections/diagnosis , Filoviridae Infections/prevention & control , Filoviridae Infections/veterinary , Forecasting/methods , Hemorrhagic Fever, Ebola/epidemiology , Hemorrhagic Fever, Ebola/prevention & control , Hemorrhagic Fever, Ebola/veterinary , Humans , Population Forecast , Zoonoses/epidemiology , Zoonoses/prevention & controlABSTRACT
Nucleic acid testing (NAT) for pathogenic filoviruses plays a key role in surveillance and to control the spread of infection. As they share clinical features with other pathogens, the initial spread of these viruses can be misdiagnosed. Tests that can identify a pathogen in the initial stages of infection are essential to control outbreaks. Since the Ebola virus disease (EVD) outbreak in 2014-2016 several tests have been developed that are faster than previous tests and more suited for field use. Furthermore, the ability to test for a range of pathogens simultaneously has been expanded to improve clinical pathway management of febrile syndromes. This review provides an overview of these novel diagnostic tests.
Subject(s)
Filoviridae Infections/diagnosis , Filoviridae/isolation & purification , Molecular Diagnostic Techniques/methods , RNA, Viral/isolation & purification , Humans , RNA, Viral/geneticsABSTRACT
BACKGROUND: A unit of the European Mobile Laboratory (EMLab) consortium was deployed to the Ebola virus disease (EVD) treatment unit in Guéckédou, Guinea, from March 2014 through March 2015. METHODS: The unit diagnosed EVD and malaria, using the RealStar Filovirus Screen reverse transcription-polymerase chain reaction (RT-PCR) kit and a malaria rapid diagnostic test, respectively. RESULTS: The cleaned EMLab database comprised 4719 samples from 2741 cases of suspected EVD from Guinea. EVD was diagnosed in 1231 of 2178 hospitalized patients (57%) and in 281 of 563 who died in the community (50%). Children aged <15 years had the highest proportion of Ebola virus-malaria parasite coinfections. The case-fatality ratio was high in patients aged <5 years (80%) and those aged >74 years (90%) and low in patients aged 10-19 years (40%). On admission, RT-PCR analysis of blood specimens from patients who died in the hospital yielded a lower median cycle threshold (Ct) than analysis of blood specimens from survivors (18.1 vs 23.2). Individuals who died in the community had a median Ct of 21.5 for throat swabs. Multivariate logistic regression on 1047 data sets revealed that low Ct values, ages of <5 and ≥45 years, and, among children aged 5-14 years, malaria parasite coinfection were independent determinants of a poor EVD outcome. CONCLUSIONS: Virus load, age, and malaria parasite coinfection play a role in the outcome of EVD.
Subject(s)
Ebolavirus/isolation & purification , Epidemics , Filoviridae Infections/diagnosis , Hemorrhagic Fever, Ebola/diagnosis , Malaria/complications , Mobile Health Units , Adolescent , Adult , Aged , Child , Child, Preschool , Clinical Laboratory Services , Ebolavirus/genetics , Female , Filoviridae , Filoviridae Infections/complications , Filoviridae Infections/virology , Guinea , Hemorrhagic Fever, Ebola/complications , Hemorrhagic Fever, Ebola/virology , Humans , Infant , Malaria/parasitology , Male , Middle Aged , RNA, Viral/blood , Viral Load , Young AdultABSTRACT
BACKGROUND: Diagnosis of Ebola virus (EBOV) disease (EVD) requires laboratory testing. METHODS: The RealStar Filovirus Screen reverse transcription-polymerase chain reaction (RT-PCR) kit and the derived RealStar Zaire Ebolavirus RT-PCR kit were validated using in vitro transcripts, supernatant of infected cell cultures, and clinical specimens from patients with EVD. RESULTS: The Filovirus Screen kit detected EBOV, Sudan virus, Taï Forest virus, Bundibugyo virus, Reston virus, and Marburg virus and differentiated between the genera Ebolavirus and Marburgvirus The amount of filovirus RNA that could be detected with a probability of 95% ranged from 11 to 67 RNA copies/reaction on a LightCycler 480 II. The Zaire Ebolavirus kit is based on the Filovirus Screen kit but was optimized for detection of EBOV. It has an improved signal-to-noise ratio at low EBOV RNA concentrations and is somewhat more sensitive than the Filovirus kit. Both kits show significantly lower analytical sensitivity on a SmartCycler II. Clinical evaluation revealed that the SmartCycler II, compared with other real-time PCR platforms, decreases the clinical sensitivity of the Filovirus Screen kit to diagnose EVD at an early stage. CONCLUSIONS: The Filovirus Screen kit detects all human-pathogenic filoviruses with good analytical sensitivity if performed on an appropriate real-time PCR platform. High analytical sensitivity is important for early diagnosis of EVD.
Subject(s)
Ebolavirus/isolation & purification , Filoviridae Infections/diagnosis , Filoviridae/isolation & purification , Hemorrhagic Fever, Ebola/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/methods , Ebolavirus/genetics , Filoviridae/genetics , Filoviridae Infections/virology , Hemorrhagic Fever, Ebola/virology , Humans , Pathology, Molecular , RNA, Viral/analysis , RNA, Viral/genetics , Reagent Kits, Diagnostic , Sensitivity and SpecificityABSTRACT
BACKGROUND: Cutaneous viral infections are increasing in recent years, particularly in immunocompromised patients. OBJECTIVE: Immunohistochemistry (IHC) provides a rapid and helpful tool that can be applied to confirm the diagnosis of specific viral infections that may be difficult to diagnose with certainty using routine microscopy alone. METHODS: Several immunostains that are useful in histopathology have been reviewed and tested in cutaneous samples of viral infections. Emphasis is placed on new stains and novel uses of existing stains. RESULTS: This article is an up-to-date overview of the potential uses of IHC in the histopathologic diagnosis of cutaneous viral infections by parvoviruses, polyomaviruses, poxviruses, paramyxoviridae, picornaviridae, retroviruses, and filoviruses. LIMITATIONS: Specific monoclonal antibodies are commercially available only for some members of these virus families. CONCLUSIONS: IHC may assist dermatopathologists to appropriately diagnose viral infections by parvoviruses, polyomaviruses, poxviruses, paramyxoviridae, picornaviridae, retroviruses, and filoviruses.
Subject(s)
Antigens, Viral/immunology , Filoviridae Infections/diagnosis , Immunohistochemistry , Paramyxoviridae Infections/diagnosis , Parvoviridae Infections/diagnosis , Picornaviridae Infections/diagnosis , Poxviridae Infections/diagnosis , Retroviridae Infections/diagnosis , Skin Diseases, Viral/diagnosis , Skin/immunology , Antibodies, Monoclonal , Biomarkers/analysis , Biopsy , Filoviridae Infections/immunology , Filoviridae Infections/pathology , Filoviridae Infections/virology , Humans , Paramyxoviridae Infections/immunology , Paramyxoviridae Infections/pathology , Paramyxoviridae Infections/virology , Parvoviridae Infections/immunology , Parvoviridae Infections/pathology , Parvoviridae Infections/virology , Picornaviridae Infections/immunology , Picornaviridae Infections/pathology , Picornaviridae Infections/virology , Poxviridae Infections/immunology , Poxviridae Infections/pathology , Poxviridae Infections/virology , Predictive Value of Tests , Retroviridae Infections/immunology , Retroviridae Infections/pathology , Retroviridae Infections/virology , Skin/pathology , Skin/virology , Skin Diseases, Viral/immunology , Skin Diseases, Viral/pathology , Skin Diseases, Viral/virologyABSTRACT
OBJECTIVE: Marburg virus and Ebola virus are acute infections with high case fatality rates. A rapid, sensitive detection method was established to detect Marburg virus and Ebola virus by multiplex real-time fluorescence quantitative PCR. METHODS: Designing primers and Taqman probes from highly conserved sequences of Marburg virus and Ebola virus through whole genome sequences alignment, Taqman probes labeled by FAM and Texas Red, the sensitivity of the multiplex real-time quantitative PCR assay was optimized by evaluating the different concentrations of primers and Probes. RESULTS: We have developed a real-time PCR method with the sensitivity of 30.5 copies/microl for Marburg virus positive plasmid and 28.6 copies/microl for Ebola virus positive plasmids, Japanese encephalitis virus, Yellow fever virus, Dengue virus were using to examine the specificity. CONCLUSIONS: The Multiplex real-time PCR assays provide a sensitive, reliable and efficient method to detect Marburg virus and Ebola virus simultaneously.
Subject(s)
Ebolavirus/genetics , Filoviridae Infections/virology , Hemorrhagic Fever, Ebola/virology , Marburgvirus/genetics , Multiplex Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/methods , Ebolavirus/isolation & purification , Filoviridae Infections/diagnosis , Hemorrhagic Fever, Ebola/diagnosis , Humans , Marburgvirus/isolation & purificationABSTRACT
Filovirus infection presents many unique challenges to patient management. Currently no approved treatments are available, and the recommendations for supportive care are not evidence based. The austere clinical settings in which patients often present and the sporadic and at times explosive nature of filovirus outbreaks have effectively limited the information available to evaluate potential management strategies. This review will summarize the management approaches used in filovirus outbreaks and provide recommendations for collecting the information necessary for evaluating and potentially improving patient outcomes in the future.
Subject(s)
Filoviridae Infections/diagnosis , Filoviridae Infections/therapy , Filoviridae/isolation & purification , Disease Outbreaks , Filoviridae Infections/epidemiology , Filoviridae Infections/pathology , Humans , Treatment OutcomeABSTRACT
Several enzyme-linked immunosorbent assays (ELISAs) for the detection of filovirus-specific antibodies have been developed. However, diagnostic methods to distinguish antibodies specific to the respective species of filoviruses, which provide the basis for serological classification, are not readily available. We established an ELISA using His-tagged secreted forms of the transmembrane glycoproteins (GPs) of five different Ebola virus (EBOV) species and one Marburg virus (MARV) strain as antigens for the detection of filovirus species-specific antibodies. The GP-based ELISA was evaluated by testing antisera collected from mice immunized with virus-like particles as well as from humans and nonhuman primates infected with EBOV or MARV. In our ELISA, little cross-reactivity of IgG antibodies was observed in most of the mouse antisera. Although sera and plasma from some patients and monkeys showed notable cross-reactivity with the GPs from multiple filovirus species, the highest reactions of IgG were uniformly detected against the GP antigen homologous to the virus species that infected individuals. We further confirmed that MARV-specific IgM antibodies were specifically detected in specimens collected from patients during the acute phase of infection. These results demonstrate the usefulness of our ELISA for diagnostics as well as ecological and serosurvey studies.
Subject(s)
Antibodies, Viral/blood , Antigens, Viral , Filoviridae Infections/diagnosis , Filoviridae Infections/veterinary , Filoviridae/isolation & purification , Virology/methods , Animals , Antigens, Viral/genetics , Cross Reactions , Ebolavirus/genetics , Ebolavirus/immunology , Enzyme-Linked Immunosorbent Assay/methods , Female , Filoviridae/immunology , Filoviridae Infections/immunology , Haplorhini , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Marburgvirus/genetics , Marburgvirus/immunology , Mice , Mice, Inbred BALB C , Primates , Recombinant Proteins/genetics , Sensitivity and SpecificitySubject(s)
Filoviridae Infections , Filoviridae , Animals , Antiviral Agents/therapeutic use , Disease Outbreaks , Disease Reservoirs , Filoviridae/isolation & purification , Filoviridae/physiology , Filoviridae/ultrastructure , Filoviridae Infections/diagnosis , Filoviridae Infections/epidemiology , Filoviridae Infections/therapy , Genome, Viral , Global Health , Humans , Viral VaccinesABSTRACT
Filoviruses have the capacity to cause lethal outbreaks of hemorrhagic fever in primates. Here we present a simple consensus reverse transcription-PCR method for filovirus recognition and characterization and demonstrate its utility with all known filovirus strains. Phylogenetic assignment is achieved by automated web-based sequence analysis of amplification products.
Subject(s)
Filoviridae Infections/diagnosis , Filoviridae Infections/virology , Filoviridae/classification , Filoviridae/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/methods , Animals , Ebolavirus/genetics , Ebolavirus/isolation & purification , Filoviridae/genetics , Hemorrhagic Fever, Ebola , Humans , Marburg Virus Disease , Marburgvirus/genetics , Marburgvirus/isolation & purification , Phylogeny , Sensitivity and Specificity , Time FactorsABSTRACT
OBJECTIVE: To develop consensus-based recommendations for measures to be taken by medical and public health professionals if hemorrhagic fever viruses (HFVs) are used as biological weapons against a civilian population. PARTICIPANTS: The Working Group on Civilian Biodefense included 26 representatives from academic medical centers, public health, military services, governmental agencies, and other emergency management institutions. EVIDENCE: MEDLINE was searched from January 1966 to January 2002. Retrieved references, relevant material published prior to 1966, and additional sources identified by participants were reviewed. CONSENSUS PROCESS: Three formal drafts of the statement that synthesized information obtained in the evidence-gathering process were reviewed by the working group. Each draft incorporated comments and judgments of the members. All members approved the final draft. CONCLUSIONS: Weapons disseminating a number of HFVs could cause an outbreak of an undifferentiated febrile illness 2 to 21 days later, associated with clinical manifestations that could include rash, hemorrhagic diathesis, and shock. The mode of transmission and clinical course would vary depending on the specific pathogen. Diagnosis may be delayed given clinicians' unfamiliarity with these diseases, heterogeneous clinical presentation within an infected cohort, and lack of widely available diagnostic tests. Initiation of ribavirin therapy in the early phases of illness may be useful in treatment of some of these viruses, although extensive experience is lacking. There are no licensed vaccines to treat the diseases caused by HFVs.
Subject(s)
Arenaviridae Infections/prevention & control , Biological Warfare , Bioterrorism , Bunyaviridae Infections/prevention & control , Civil Defense/standards , Filoviridae Infections/prevention & control , Flavivirus Infections/prevention & control , Hemorrhagic Fevers, Viral/prevention & control , Public Health Administration/standards , Public Health Practice/standards , Aerosols , Antiviral Agents/therapeutic use , Arenaviridae/pathogenicity , Arenaviridae Infections/diagnosis , Arenaviridae Infections/drug therapy , Arenaviridae Infections/epidemiology , Arenaviridae Infections/transmission , Bunyaviridae/pathogenicity , Bunyaviridae Infections/diagnosis , Bunyaviridae Infections/drug therapy , Bunyaviridae Infections/epidemiology , Bunyaviridae Infections/transmission , Cadaver , Clinical Laboratory Techniques , Disaster Planning/standards , Disease Outbreaks/prevention & control , Filoviridae/pathogenicity , Filoviridae Infections/diagnosis , Filoviridae Infections/drug therapy , Filoviridae Infections/epidemiology , Filoviridae Infections/transmission , Flaviviridae/pathogenicity , Flavivirus Infections/diagnosis , Flavivirus Infections/drug therapy , Flavivirus Infections/epidemiology , Flavivirus Infections/transmission , Hemorrhagic Fevers, Viral/diagnosis , Hemorrhagic Fevers, Viral/drug therapy , Hemorrhagic Fevers, Viral/epidemiology , Hemorrhagic Fevers, Viral/transmission , Infection Control , Research , Ribavirin/therapeutic use , United States , Viral VaccinesABSTRACT
Epidemiological issues, clinical course and laboratory diagnostics of Ebola haemorrhagic fever are reviewed. The structural features of virions and genetic variants of the virus are described along with ecology of Ebola virus. The data on Ebola fever global morbidity are also presented.
Subject(s)
Ebolavirus , Filoviridae Infections/epidemiology , Hemorrhagic Fever, Ebola/epidemiology , Cote d'Ivoire/epidemiology , Democratic Republic of the Congo/epidemiology , Ecology , Filoviridae Infections/diagnosis , Filoviridae Infections/prevention & control , Gabon/epidemiology , Genetic Variation , Hemorrhagic Fever, Ebola/diagnosis , Hemorrhagic Fever, Ebola/prevention & control , Humans , Kenya/epidemiology , Morbidity , Sudan/epidemiology , Uganda/epidemiologyABSTRACT
Sensationalised accounts of wards of dying patients have fueled intense public fascination with filoviruses and highlighted the global threat of emerging and re-emerging infectious diseases. Filoviruses are the prototypical emerging pathogens: they cause a haemorrhagic disease of high case-fatality associated with explosive outbreaks due to person-to-person transmission, have no known treatment, occur unpredictably, and have an unknown reservoir. In truth, since their initial discovery in 1967, only a handful of filoviral outbreaks have occurred, mostly in remote locations. However, the documented occurrence of secondary cases in locations far from endemic areas validates the concern that filoviruses have the potential to cause unprecedented outbreaks in the future.