Global patterns and drivers of influenza decline during the COVID-19 pandemic.

OBJECTIVES: The influenza circulation reportedly declined during the COVID-19 pandemic in many countries. The occurrence of this change has not been studied worldwide nor its potential drivers. METHODS: The change in the proportion of positive influenza samples reported by country and trimester was computed relative to the 2014-2019 period using the FluNet database. Random forests were used to determine predictors of change from demographical, weather, pandemic preparedness, COVID-19 incidence, and pandemic response characteristics. Regression trees were used to classify observations according to these predictors. RESULTS: During the COVID-19 pandemic, the influenza decline relative to prepandemic levels was global but heterogeneous across space and time. It was more than 50% for 311 of 376 trimesters-countries and even more than 99% for 135. COVID-19 incidence and pandemic preparedness were the two most important predictors of the decline. Europe and North America initially showed limited decline despite high COVID-19 restrictions; however, there was a strong decline afterward in most temperate countries, where pandemic preparedness, COVID-19 incidence, and social restrictions were high; the decline was limited in countries where these factors were low. The "zero-COVID" countries experienced the greatest decline. CONCLUSION: Our findings set the stage for interpreting the resurgence of influenza worldwide.

First Detection of the Adventive Egg Parasitoid of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) Trissolcus mitsukurii (Ashmead) (Hymenoptera: Scelionidae) in France.

We report the first detection of Trissolcus mitsukurii in France. More than 1860 sentinel egg masses of Halyomorpha halys (BMSB) were exposed in the field during the 2018-2020 period, and 12 specimens of T. mitsukurii emerged from one egg mass. Their taxonomic identification was confirmed both by morphological and molecular analysis. Trissolcus mitsukurii, similar to T. japonicus, is an egg parasitoid of BMSB in its area of origin in Asia, and both species are considered to be candidates for a classical biological control strategy against BMSB. Trissolcus mitsukurii was previously recorded in Italy where it is well established and widespread, and this may be the source of the French population. Possible permanent establishment and dispersion of T. mitsukurii in France should be monitored with emphasis on its potential effect on BMSB populations.

Vincristine induces procoagulant activity of the human lymphoblastic leukemia cell line Jurkat through the release of extracellular vesicles.

Thromboembolic events are frequent and serious complications of acute lymphoblastic leukaemia treatment. The importance of chemotherapy in the pathogenesis of this increased risk is enhanced by the fact that thrombosis rarely occurs at diagnosis. Our study aims at investigating the effect of chemotherapy on pro-coagulant activity (PCA), phosphatidylserine (PS) exposure, tissue factor (TF) activity and derived extracellular vesicles (EV) of Jurkat cells. Jurkat cells were treated with two commonly used chemotherapeutics: Vincristine (VCR) or Daunorubicin (DNR), at relevant concentrations. PCA of cells and derived EV were evaluated using Thrombin generation Assay (TGA). Cells or EV were incubated with annexin V or anti TF antibodies to assess the respective contribution of TF and PS. PS exposure on cells was analysed by flow cytometry. Derived EV were evaluated in fluorescence microscopy and flow cytometry. Untreated Jurkat cells and EV support thrombin generation. Thrombin generation was abolished when PS activity was inhibited by annexin V. VCR treatment resulted in a time dependent increase of thrombin generation. After VCR exposure, TF activity increased as well as PS exposure increased on the cell surface. The increase in TF activity was abolished by annexin V indicating that PS was required. A spontaneous release of EV from Jurkat cells was observed and VCR treatment increased the number of generated EV. Our results indicate that VCR increased the PCA of Jurkat cells predominantly through PS exposure and increased EV generation. Lymphoid blasts derived EV could be biomarkers to determine high thrombotic risk ALL patients.

Applications of Extreme Value Theory in Public Health.

OBJECTIVES: We present how Extreme Value Theory (EVT) can be used in public health to predict future extreme events. METHODS: We applied EVT to weekly rates of Pneumonia and Influenza (P&I) deaths over 1979-2011. We further explored the daily number of emergency department visits in a network of 37 hospitals over 2004-2014. Maxima of grouped consecutive observations were fitted to a generalized extreme value distribution. The distribution was used to estimate the probability of extreme values in specified time periods. RESULTS: An annual P&I death rate of 12 per 100,000 (the highest maximum observed) should be exceeded once over the next 30 years and each year, there should be a 3% risk that the P&I death rate will exceed this value. Over the past 10 years, the observed maximum increase in the daily number of visits from the same weekday between two consecutive weeks was 1133. We estimated at 0.37% the probability of exceeding a daily increase of 1000 on each month. CONCLUSION: The EVT method can be applied to various topics in epidemiology thus contributing to public health planning for extreme events.

Location of sulfate groups on sulfoacetate derivatives of cellulose.

A water-soluble cellulose acetate sulfate (CAS) with a degree of acetylation (DS(Ac)) 2.4 and a degree of sulfation (DS(Sulf)) of 0.3 was obtained by direct acetylation of cellulose using sulfuric acid as catalyst. Using methylation analysis, IR and NMR spectroscopy, sulfate groups have been located on primary alcohol function of glucose residues. The distribution of the sulfate groups along the cellulose chain has been investigated using enzymatic hydrolysis. CAS was first de-acetylated under mild hydrolysis conditions (NaOH 0.25 mol/L at room temperature), and then cellulose sulfate was hydrolyzed by a cellulolytic complex (Celluclast 1.5L). Reaction products were separated by ion exchange chromatography on a DEAE Sepharose CL6B column into five fractions F(1), F(2), F(3), F(4) and F(5), which were analyzed for their chemical composition. F(1) was glucose and represented the main product of reaction (approximately 50% of the initial glucose), F(2) was a dimer (approximately 30%) with a ratio Sulfates-Glucose of 0.41 (about one sulfate group for two glucose units), F(3) a trimer (approximately 10%) with a ratio Sulfates-Glucose of 0.62 (about two sulfate groups for three glucose units), and F(4) a tetramer (approximately 5%) with a ratio Sulfates-Glucose of 0.69. The structure of the oligomers was established using 1H and 13C NMR. The observed proportion of the different blocks of sulfate groups was in good agreement with computed random distribution.