[Field assessment of the new rapid diagnostic test Ebola eZYSCREEN®]. / Validation sur le terrain du nouveau test de diagnostic rapide Ebola eZYSCREEN®.

During the Ebola virus disease outbreak in West Africa in 2014, the World Health Organization has pointed out the need for rapid diagnostic tests (RDT) affordable, sensitive, specific, user-friendly, rapid, equipment-free, and deliverable. The rapid diagnostic test (Lateral Flow Assay) Ebola eZYSCREEN® was developed in this emergency frame using monoclonal antibodies against the envelope glycoprotein of the virus. Two distinct versions have been industrialized, one for whole-blood samples and the other for serum/plasma samples. Both versions have an analytical detection limit of 105 pfu/ml, the stability is at least 393 days at 30°C and 120 days at 45°C. The nonretrospective and independent validation study was carried out in the course of the outbreak in Conakry and at the Ebola Treatment Center of Coyah (Guinea) on 144 patients. In this study, the RDT showed a sensitivity of 65.3% and a specificity of 98.9% on whole blood, a sensitivity of 74.5% and a specificity of 100% on serum. Results from the whole-blood version must be analyzed with caution because of the delay between the blood collection and the completion of the tests, which was out of specification (3 days on average instead of 2 h). In contrast to laboratory tests, this easy to use field test does not require sophisticated instrumentation or even electricity and can contribute to the diagnostic chain of Ebola virus disease taking into account its benefits, high stability, and specificity but also its limit of sensitivity compared to laboratory techniques RT-qPCR (Real-Time reverse transcription Polymerase Chain Reaction), which remain the reference for the diagnosis of Ebola. The RDT Ebola eZYSCREEN® was granted EC IVD (IVD = In Vitro Diagnostic) marking.

Evaluation of Crimean-Congo hemorrhagic fever virus in vitro inhibition by chloroquine and chlorpromazine, two FDA approved molecules.

Crimean-Congo hemorrhagic virus (CCHFV) causes hemorrhagic fever with high case mortality rates and is endemic in south-eastern Europe, Africa, and Asia. The limited catalog of specific treatment, highlight the necessity to look for additional therapeutic solutions. Previous experiments suggested that CCHFV enters the cells via a clathrin dependent pathway. Therefore, we have evaluated the potential anti-CCHFV activity of several molecules targeting this entry possibility. We identified two molecules chloroquine and chlorpromazine. Neutralization and virus yield reduction assays were tested in Vero E6 and Huh7 cells on two different CCHFV strains. Several combinations, including ribavirin, were assayed to test a potential synergistic effect. The two molecules inhibited CCHFV, and depending on the virus and the cell lines, the 50% inhibitory concentration (IC50) values for chloroquine and chlorpromazine ranged from 28 to 43 and 10.8-15.7 µM, respectively. Time-of-addition studies demonstrated that these molecules had a direct effect on CCHFV infectivity and spread. The antiviral activity of the two molecules was still effective even when added up to 6h post-infection and up to 24h. The selectivity index ranging from 3 to 35 lead us to evaluate combinations with ribavirin. Combinations of ribavirin and chloroquine or chlorpromazine were synergistic against CCHFV. Though the low chlorpromazine selectivity index suggests the need for a chemical improvement, our present study highlights chloroquine as the main drug having the potential for drug repurposing.

Development of a one step real time RT-PCR assay to detect and quantify Dugbe virus.

A one-step real time quantitative RT-PCR (qRT-PCR) assay was developed to detect all published Dugbe virus (DUGV) genomes of the Nairovirus genus. Primers and probes were designed to detect specific sequences on the most conserved regions of the S segment. The limit of detection of the assay was 10 copies per reaction which is an improvement of 3 log(10)FFU/mL over the sensitivity of conventional RT-PCR. The specificity of the primers and probe was confirmed with the closely related Nairoviruses CCHFV and Hazara virus, and on the non-related viruses Coronavirus and Influenza A virus. This qRT-PCR assay was used to screen nucleic acids extracted from 498 ticks collected in the Republic of Chad. One sample was found positive suggesting that DUGV is present in this part of the world. The molecular assay developed in this study is sensitive, specific and rapid and can be used for research and epidemiological studies.

[Crimean-Congo hemorrhagic fever: basics for general practitioners]. / La fièvre hémorragique de Crimée-Congo: l'essentiel pour le praticien.

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne disease described in more than 30 countries in Europe, Asia and Africa. The causative agent is the Crimean-Congo hemorrhagic fever virus (CCHFV) that is a member of the genus Nairovirus of the family Bunyaviridae. CCHFV that is characterized by a high genetic variability is transmitted to humans by tick bites or contact with fluids from an infected individual or animal. The initial symptoms of CCHF are nonspecific and gradually progress to a hemorrhagic phase that can be lethal (case-fatality rate: 10 to 50%). Characteristic laboratory findings of CCHF are thrombocytopenia, elevated liver and muscle enzymes, and coagulation defects. The pathogenesis of CCHF remains unclear but might involve excessive pro-inflammatory cytokine production and dysfunction of the innate immune response. Diagnosis of CCHF is based mainly on isolation of the virus, identification of the viral genome by molecular techniques (RT-PCR), and serological detection of anti-CCHFV antibodies. There is currently no specific treatment for CCHFV infection and the efficacy of ribavirin is controversial. In absence of an effective vaccine, prevention is based mainly on vector control, protection measures, and information to increase the awareness of the population and of healthcare workers.

Epidemic resurgence of Chikungunya virus in democratic Republic of the Congo: identification of a new central African strain.

The resurgence of Chikungunya virus is described during an urban epidemic in Kinshasa Democratic Republic of the Congo, after 39 years without any isolation of the virus. Chikungunya virus was isolated in sera from nine patients with clinical symptoms. A 1,200 bp long partial sequence of the E1/3'UTR genomic region was determined for each isolate. All sequences clustered in the central African lineage. They constitute Chikungunya virus reference sequences for the Democratic Republic of the Congo.