ETIDIOH - NEW

Summary Background Latin America has been experiencing an Oropouche virus (OROV) outbreak of unprecedented magnitude and spread since 2023–24 for unknown reasons. We aimed to identify risk predictors of and areas at risk for OROV transmission. Methods In this multidisciplinary, laboratory-based, modelling study, we retrospectively tested anonymised serum samples collected between 2001 and 2022 for studies on virus epidemiology and medical diagnostics in Bolivia, Brazil, Colombia, Costa Rica, Ecuador, and Peru with nucleoprotein-based commercial ELISAs for OROV-specific IgG and IgM antibodies. Serum samples positive for IgG from different ecological regions and sampling years were tested against Guaroa virus and two OROV glycoprotein reassortants (Iquitos virus and Madre de Dios virus) via plaque reduction neutralisation testing (PRNT) to validate IgG ELISA specificity and support antigenic cartography. Three OROV strains were included in the neutralisation testing, a Cuban OROV isolate...

Abstract The continuous spread of highly pathogenic avian influenza H5 viruses poses significant challenges, particularly in regions with high poultry farm densities where conventional control measures are less effective. Using phylogeographic and phylodynamic tools , we analysed virus spread in Southwestern France in 2020-21, a region with recurrent outbreaks. Following a single introduction, the virus spread regionally, mostly affecting duck farms , peaking in mid-December with a velocity of 27.8 km/week and an effective reproduction number between farms (Re) of 3.8, suggesting the virus can spread beyond current control radii. Transmission declined after late December following preventive culling. Farm infectiousness was estimated around 9 days. Duck farm density was the main driver of virus spread and we identified farm density and proximity thresholds required to maintain effective control (Re < 1). These findings offer actionable guidance to support regional biosecurity and to...

Abstract We modeled the impact of initiating one-dose influenza vaccination at 3 months vs 6 months after declaration of a pandemic over a 1-year timeframe in the US population. Three vaccine effectiveness (VE) and two pandemic severity levels were considered, using an epidemic curve based on typical seasonal influenza epidemics. Vaccination from 3 months with a high, moderate, or low effectiveness vaccine would prevent ~95%, 84%, or 38% deaths post-vaccination, respectively, compared with 21%, 18%, and 8%, respectively following vaccination at 6 months, irrespective of pandemic severity. While the pandemic curve would not be flattened from vaccination from 6 months , a moderate/high effectiveness vaccine could flatten the curve if administered from 3 months. Overall, speed of initiating a vaccination campaign is more important than VE in reducing the health impacts of an influenza pandemic. Preparedness strategies may be able to minimize future pandemic impacts by prioritizing rapid v...

Abstract Understanding the transmission routes of high-pathogenicity avian influenza (HPAI) is crucial for developing effective control measures to prevent its spread. In this context, windborne transmission , the idea that the virus can travel through the air over considerable distances, is a contentious concept and, documented cases are rare. Here, though, we provide genetic evidence supporting the feasibility of windborne transmission . During the 2023-24 HPAI season, molecular surveillance identified identical H5N1 strains among a cluster of unrelated commercial farms about 8 km apart in the Czech Republic . The episode started with the abrupt mortality of fattening ducks on one farm and was followed by disease outbreaks at two nearby high-biosecurity chicken farms. Using genetic, epizootiological, meteorological and geographical data , we reconstructed a mosaic of events strongly suggesting wind was the mechanism of infection transmission between poultry in at least two independen...

Abstract Background For decades after the identification of mpox in humans in the Democratic Republic of Congo (DRC) in 1970, the disease was largely confined to the rural areas of Central and West Africa and thus did not garner broad attention. On August 13, 2024, mpox was declared a Public Health Emergency of Continental Security (PHECS) by the Africa Centers for Disease Control and Prevention (Africa CDC), a notice that was followed the next day by a declaration of a Public Health Emergency of International Concern (PHEIC) by the World Health Organization. Methods In this study we analyzed all mpox cases and deaths , based on clinical or laboratory diagnosis, that were reported to the Africa CDC from January 1, 2022, to October 30, 2024, to identify temporal variations, geographic distributions, and epidemiologic trends. Results From January 1, 2022, to August 18, 2024, a total of 45,652 mpox cases were clinically diagnosed and laboratory-confirmed in 12 African countries . These ca...

Summary Background DR Congo has the highest global burden of mpox , a disease caused by infection with the monkeypox virus . The incidence has risen since 1980, but recent analyses of epidemiological trends are lacking. We aimed to describe trends in suspected and confirmed mpox cases in DR Congo using epidemiological and laboratory mpox surveillance data collected from 2010 to 2023, and provide insights that can better inform the targeting and monitoring of control strategies. Methods We analysed aggregated national epidemiological surveillance data and individual-level laboratory data from 2010 to 2023. We calculated incidence based on suspected cases, case-fatality ratios, and percentage of laboratory-confirmed cases and assessed geospatial trends. Demographic and seasonal trends were investigated using generalised additive mixed models. Findings Between Jan 1, 2010, and Dec 31, 2023, a total of 60 967 suspected cases and 1798 suspected deaths from mpox were reported in DR Congo ( c...

Abstract We present a stochastic metapopulation transmission model that simulates the spread of H5N1 avian influenza through individual dairy cows in 35,974 dairy herds in the continental United States . Transmission is enabled through the movement of cattle between herds , as indicated from Interstate Certificates of Veterinary Inspection (ICVI) data. We estimate the rates of under-reporting by state and present the anticipated rates of positivity for cattle tested at the point of exportation over time. We investigate the likely impact of intervention methods to date on the underlying epidemiological dynamics, demonstrating that current interventions have had insufficient impact , preventing only a mean 175.2 reported outbreaks. Our model predicts that the majority of the disease burden is, as of January 2025, concentrated within West Coast states , due to the network of cattle movements and distribution of the respective dairy populations . We quantify the extent of uncertainty in th...

Abstract The generation time , representing the interval between infections in primary and secondary cases , is essential for understanding and predicting the transmission dynamics of seasonal influenza , including the real-time effective reproduction number (Rt). However, comprehensive generation time estimates for seasonal influenza, especially since the 2009 influenza pandemic, are lacking. We estimated the generation time utilizing data from a 7-site case-ascertained household study in the United States over two influenza seasons, 2021/2022 and 2022/2023. More than 200 individuals who tested positive for influenza and their household contacts were enrolled within 7 days of the first illness in the household. All participants were prospectively followed for 10 days, completing daily symptom diaries and collecting nasal swabs, which were then tested for influenza via RT-PCR. We analyzed these data by modifying a previously published Bayesian data augmentation approach that imputes in...