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International audience; We report the whole-genome sequences of a monkeypox virus from the skin lesion of a French patient and the corresponding isolated viral strain. Both viral genomic sequences were successfully obtained by applying shotgun metagenomics using the Oxford Nanopore Technologies sequencing approach.

Different kinds of media spiked with Monkeypoxvirus (MPXV) were subjected to heat inactivation at different temperatures, for various periods of time. Our results showed that MPXV was inactivated in less than 5 min at 70 °C and in less than 15 min at 60 °C, with no difference between virus from West African and Central African clades. Such indications could help laboratory workers to manipulate the virus in optimal biosafety conditions and improve their protocols.

During outbreaks, the lack of diagnostic “gold standard” can mask the true burden of infection in the population and hamper the allocation of resources required for control. Here, we present an analytical framework to evaluate and optimize the use of diagnostics when multiple yet imperfect diagnostic tests are available. We apply it to laboratory results of 2,136 samples, analyzed with three diagnostic tests (based on up to seven diagnostic outcomes), collected during the 2017 pneumonic (PP) and bubonic plague (BP) outbreak in Madagascar, which was unprecedented both in the number of notified cases, clinical presentation, and spatial distribution. The extent of this outbreaks has however remained unclear due to non-optimal assays. Using latent class methods, we estimate that 7%-15% of notified cases were Yersinia pestis-infected. Overreporting was highest during the peak of the outbreak and lowest in the rural settings endemic to Yersinia pestis. Molecular biology methods offered the best compromise between sensitivity and specificity. The specificity of the rapid diagnostic test was relatively low (PP: 82%, BP: 85%), particularly for use in contexts with large quantities of misclassified cases. Comparison with data from a subsequent seasonal Yersinia pestis outbreak in 2018 reveal better test performance (BP: specificity 99%, sensitivity: 91%), indicating that factors related to the response to a large, explosive outbreak may well have affected test performance. We used our framework to optimize the case classification and derive consolidated epidemic trends. Our approach may help reduce uncertainties in other outbreaks where diagnostics are imperfect.

ObjectivesDetermine the sensitivity and specificity of a Point-Of-Care test (‘COVIDISC’) for SARS-COV2. The novelty of the test is to integrate, on the same (low-cost) compact plastic/paper device, solid phase RNA extraction and RT-LAMP amplification, all reagents being freeze-dried on it.MethodRetrospective study with a cohort of 99 patients characterized by real-time RT-PCR. The 37 positive naso-pharyngeal samples cover a broad range of viral loads (from 5 gc /µL to 2 106gc/ µL of sample).ResultsThe COVIDISC found 36 positives (out of 37 by IP4 RT-PCR protocols) and 63 negatives (out of 62 by RT-PCR).ConclusionThe sensitivity of the COVIDISC, found in this 99-patient retrospective study, is 97% and the specificity 100%.

International audience; Methods for virus particle quantification represent a critical aspect of many virology studies. Although several reliable techniques exist, they are either time-consuming or unable to detect small variations. Presented here is a protocol for the precise quantification of viral titer by analyzing electrical impedance variations of infected cells in real-time. Cellular impedance is measured through gold microelectrode biosensors located under the cells in microplates, in which magnitude depends on the number of cells as well as their size and shape. This protocol allows real-time analysis of cell proliferation, viability, morphology and migration with enhanced sensitivity. Also provided is an example of a practical application by quantifying the decay of influenza A virus (IAV) submitted to various physicochemical parameters affecting viral infectivity over time (i.e., temperature, salinity, and pH). For such applications, the protocol reduces the workload needed while also generating precise quantification data of infectious virus particles. It allows the comparison of inactivation slopes among different IAV, which reflects their capacity to persist in given environment. This protocol is easy to perform, is highly reproducible, and can be applied to any virus producing cytopathic effects in cell culture.

Supernatants of cells infected with SARS-CoV-2, nasopharyngeal and sera samples containing SARS-CoV-2 were submitted to heat inactivation for various periods of time, ranging from 30 seconds to 60 minutes. Our results showed that SARS-CoV-2 could be inactivated in less than 30 minutes, 15 minutes and 3 minutes at 56°C, 65°C and 95°C respectively. These data could help laboratory workers to improve their protocols with handling of the virus in biosafety conditions.

International audience; The connectedness in Arctic regions between migratory waterbird populations originating from different continents and the potential for virus exchange at their shared Arctic breeding ground point to the need to explore the largely unstudied circumpolar circulation of avian influenza viruses (AIV). We here report the investigation of AIV in wild birds and lakes in a high Arctic area of Northeast Greenland. No AIV could be detected in the fecal, feather, and water samples collected from large flocks of pink-footed geese Anser brachyrhynchus and barnacle geese Branta leucopsis in and around refuge lakes, where they congregate at high density during their flightless molting period in summer.