Comparative performance study of three Ebola rapid diagnostic tests in Guinea

Background The 2014/15 Ebola outbreak in West Africa resulted in 11,000 deaths and massive strain on local health systems, and the ongoing outbreak in Democratic Republic of Congo has afflicted more than 3000 people. Accurate, rapid Ebola diagnostics suitable for field deployment would enable prompt identification and effective response to future outbreaks, yet remain largely unavailable. The purpose of this study was to assess the accuracy of three novel rapid diagnostic tests (RDTs): an Ebola, an Ebola-Malaria, and a Fever Panel test that includes Ebola, all from a single manufacturer. Methods We evaluated the three RDTs in 109 Ebola-positive and 96 Ebola-negative stored serum samples collected during the outbreak in Guinea in 2014/15, and tested by real-time polymerase chain reaction (RT-PCR). Sensitivity, specificity, and overall percent agreement were calculated for each RDT using RT-PCR as a reference standard, stratified by Ct value ranges. Results All tests performed with high accuracy on samples with low Ct value (high viral load). The Fever Panel test performed with the highest accuracy, with a sensitivity of 89.9% and specificity of 90.6%. The Ebola and Ebola-Malaria tests performed comparably to each other: sensitivity was 77.1 and 78% respectively, and specificity was 91.7% for the Ebola test and 95.8% for the Ebola-Malaria test. Conclusions This study evaluated the accuracy of three novel rapid diagnostic tests for Ebola. The tests may have significant public health relevance, particularly the Fever Panel test, which detects seven pathogens including Ebola. Given limitations to the study resulting from uncertain sample quality, further evaluation is warranted. All tests performed with highest accuracy on samples with low Ct value (high viral load), and the data presented here suggests that these RDTs may be useful for point-of-care diagnosis of cases in the context of an outbreak. Restrictions to their use in non-severe Ebola cases or for longitudinal monitoring, when viral loads are lower, may be appropriate. Highlighting the challenge in developing and evaluating Ebola RDTs, there were concerns regarding sample integrity and reference testing, and there is a need for additional research to validate these assays

Issues of Scientific and Practical Support of Anti-Epidemic Activities in the Course of Ebola Virus Disease Epidemic Response in West Africa

Consideration is given to the experience of cooperation between the Russian Federation and the Republic of Guinea in the matter of Ebola fever response. Outlined are the challenging issues regarding scientific support of preventive activities. Provided is a brief characteristic of Pasteur Institute of Guinea as a unique platform for research activities. Covered are the legal aspects of collaboration and priority areas for the development of common initiatives in the sphere of epidemiological monitoring. Identified are the stages of material reinforcement and medical stuff capacity building, including training of specialists with a view to the establishment of effective system for epidemiological surveillance

Development and Testing of the Method for the Detection of Lassa virus RNA, Based on real-Time Polymerase Chain reaction with reverse Transcription

Abstract. Objective of the study was the development of a method for the detection and quantitative analysis (realtime RT-PCR) to identify genetic markers of Lassa virus - LASV-Fl. Materials and methods. We utilized all the available in the GenBank database (https://www.ncbi.nlm.nih.gov/genbank/) Lassa virus sequences that have been aligned to identify conservative sites applying the BioEdit 7.2.5 software package (IbisBiosciences, USA). To test the developed PCR kit, the control panel of Lassa virus RNA and pseudo-viral particles, 27 viral strains belonging to different fami­lies, as well as 37 serum samples from patients with feverish diseases selected in medical institutions of the Republic of Guinea in 2016-2018 and 55 samples of organ suspensions from multi-spiked mice were used. Results and discussion. The analytical sensitivity of the method varied from 103 copies/ml to 105 copies/ml and had 96.4 % diagnostic sensitivity, while the analytical and diagnostic specificity was 100 %. It is shown that the developed technique can be successfully introduced into practice for the detection of Lassa virus in the Republic of Guinea, using various types of material from small mammals, including whole blood and organ suspensions of M. natalensis, as well as samples of human blood sera collected 3-7 days after the onset of the disease. It is also suggested that this method can be used for strains of Lassa virus, common not only in Guinea but also in other endemic areas, but this fact must be confirmed in further studies

New data on the level of immune stratum against Q fever agent in population of the of Republic of Guinea

which is bacteria of the species Coxiella burnetii. One of the factors showing the possibility of pathogen circulation in a certain territory is assessed by the presence of an immune stratum in the inhabitants of the region. In the 1980s, the study of the immune structure of the population of the Republic of Guinea in relation to coxiellosis has begun. The present study, carried out in 2015—2019, has been aimed to obtain new information about the immune stratum of the population of the Republic of Guinea against the causative agent of Q fever and to compare it with previous studies. Specific IgG antibodies in the blood of the Guinea residents were detected by using enzyme-linked immunosorbent assay (ELISA) with a set of reagents manufactured at the St. Petersburg Pasteur Institute (St. Petersburg, Russian Federation). The serum samples were tested in at 1:100 dilution. Antibodies against C. burnetii were detected in 124/2346 (5.3% [CI 4.5-6.3]) samples. This study confirms the previously obtained data on the circulation of the causative agent of coxiellosis in all landscape and geographical zones of the Republic of Guinea. The natural and climatic conditions of the region, the variety of ixodic tick species currently inhabiting this territory being a reservoir and vector of infection, as well as a large amount of livestock are the factors for active circulation of the Q fever pathogen and the emergence of related disease outbreaks. The data obtained necessitate continuing further studies on distribution of C. burnetii in the territory of the Republic of Guinea. Taking into consideration the epidemiological significance of Q fever, a pressing task is to study a proportion of this infectious disease in the overall structure of diseases registered in the territory of the Republic of Guinea. It is also necessary to conduct regular epizootological monitoring in order to clarify the types of carriers and vectors of C. burnetii in different landscape and geographical zones of the Republic of Guinea as well as to assess the immune stratum against the pathogen in large and small cattle being the main sources of infection for humans. The data obtained will allow us to determine presence of a natural focus of this infection as well as its borders and develop a set of preventive (anti-epidemic) measures

Analysis of Ebola virus Zaire 2014 isolates

Analysis of 5 Ebola virus Zaire 2014 isolates passaged in cell cultures or in mice, demonstrated presence of unique mutations in the genome RNA in some cases. All identified nucleotide substitutions are singular, stochastically located, synonymous or fall within non-coding regions. Variability level of nucleotide sequences is equal to 0.005-0.01 %, suggesting extremely high genetic stability of Ebola virus Zaire, the causative agent of the outbreak. Confirmed is suppression of non-synonymous mutations accumulation in ebolavirus variants in the course of time. Detected are alterations in glycosilation sites and mucin-like domain of ebolavirus glycoprotein

Evaluation of Convalescent Plasma for Ebola Virus Disease in Guinea

: In the wake of the recent outbreak of Ebola virus disease (EVD) in several African countries, the World Health Organization prioritized the evaluation of treatment with convalescent plasma derived from patients who have recovered from the disease. We evaluated the safety and efficacy of convalescent plasma for the treatment of EVD in Guinea. : In this nonrandomized, comparative study, 99 patients of various ages (including pregnant women) with confirmed EVD received two consecutive transfusions of 200 to 250 ml of ABO-compatible convalescent plasma, with each unit of plasma obtained from a separate convalescent donor. The transfusions were initiated on the day of diagnosis or up to 2 days later. The level of neutralizing antibodies against Ebola virus in the plasma was unknown at the time of administration. The control group was 418 patients who had been treated at the same center during the previous 5 months. The primary outcome was the risk of death during the period from 3 to 16 days after diagnosis with adjustments for age and the baseline cycle-threshold value on polymerase-chain-reaction assay; patients who had died before day 3 were excluded. The clinically important difference was defined as an absolute reduction in mortality of 20 percentage points in the convalescent-plasma group as compared with the control group. : A total of 84 patients who were treated with plasma were included in the primary analysis. At baseline, the convalescent-plasma group had slightly higher cycle-threshold values and a shorter duration of symptoms than did the control group, along with a higher frequency of eye redness and difficulty in swallowing. From day 3 to day 16 after diagnosis, the risk of death was 31% in the convalescent-plasma group and 38% in the control group (risk difference, -7 percentage points; 95% confidence interval [CI], -18 to 4). The difference was reduced after adjustment for age and cycle-threshold value (adjusted risk difference, -3 percentage points; 95% CI, -13 to 8). No serious adverse reactions associated with the use of convalescent plasma were observed. : The transfusion of up to 500 ml of convalescent plasma with unknown levels of neutralizing antibodies in 84 patients with confirmed EVD was not associated with a significant improvement in survival. (Funded by the European Union's Horizon 2020 Research and Innovation Program and others; ClinicalTrials.gov number, NCT02342171.).<br/

Nomenclature- and Database-Compatible Names for the Two Ebola Virus Variants that Emerged in Guinea and the Democratic Republic of the Congo in 2014

In 2014, Ebola virus (EBOV) was identified as the etiological agent of a large and still expanding outbreak of Ebola virus disease (EVD) in West Africa and a much more confined EVD outbreak in Middle Africa. Epidemiological and evolutionary analyses confirmed that all cases of both outbreaks are connected to a single introduction each of EBOV into human populations and that both outbreaks are not directly connected. Coding-complete genomic sequence analyses of isolates revealed that the two outbreaks were caused by two novel EBOV variants, and initial clinical observations suggest that neither of them should be considered strains. Here we present consensus decisions on naming for both variants (West Africa: “Makona”, Middle Africa: “Lomela”) and provide database-compatible full, shortened, and abbreviated names that are in line with recently established filovirus sub-species nomenclatures

Temporal and spatial analysis of the 2014-2015 Ebola virus outbreak in West Africa

West Africa is currently witnessing the most extensive Ebola virus (EBOV) outbreak so far recorded. Until now, there have been 27,013 reported cases and 11,134 deaths. The origin of the virus is thought to have been a zoonotic transmission from a bat to a two-year-old boy in December 2013 (ref. 2). From this index case the virus was spread by human-to-human contact throughout Guinea, Sierra Leone and Liberia. However, the origin of the particular virus in each country and time of transmission is not known and currently relies on epidemiological analysis, which may be unreliable owing to the difficulties of obtaining patient information. Here we trace the genetic evolution of EBOV in the current outbreak that has resulted in multiple lineages. Deep sequencing of 179 patient samples processed by the European Mobile Laboratory, the first diagnostics unit to be deployed to the epicentre of the outbreak in Guinea, reveals an epidemiological and evolutionary history of the epidemic from March 2014 to January 2015. Analysis of EBOV genome evolution has also benefited from a similar sequencing effort of patient samples from Sierra Leone. Our results confirm that the EBOV from Guinea moved into Sierra Leone, most likely in April or early May. The viruses of the Guinea/Sierra Leone lineage mixed around June/July 2014. Viral sequences covering August, September and October 2014 indicate that this lineage evolved independently within Guinea. These data can be used in conjunction with epidemiological information to test retrospectively the effectiveness of control measures, and provides an unprecedented window into the evolution of an ongoing viral haemorrhagic fever outbreak.status: publishe

Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security