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Showing posts from March 20, 2025

St. Helena - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

On 12th September 2024, a dead Tristan (Brown) Skua (Stercorarius antarcticus hamiltoni) was found at the Gough Island helipad. The following day, a live skua was observed showing suspicious signs of HPAI , including head drooping, lethargy and weakness , and was later reported dead. Between the 12th and 15th September, a total of four skuas were found dead from suspicious causes. Three carcasses were swabbed on the 20th of September and all were confirmed POSITIVE for H5N1 HPAIV by the Animal and Plant Health Agency (Weybridge laboratory) in the UK on the 24th of October 2024. On the day of sampling, the fourth carcass could not be found and was probably taken away by a scavenging skua. Since then, no further signs of HPAI among skuas or in other seabirds breeding on Gough Island, have been observed. Source: WOAH,  https://wahis.woah.org/#/in-review/6354 ____

Post-pandemic #changes in #population #immunity have reduced the likelihood of emergence of #zoonotic #coronaviruses

Abstract Infections caused by endemic viruses , and the vaccines used to control them, often provide cross-protection against related viruses. This cross-protection has the potential to alter the transmission dynamics and likelihood of emergence of novel zoonotic viruses with pandemic potential. Here, we investigate how changes in population immunity after the COVID-19 pandemic have impacted the likelihood of emergence of a novel sarbecovirus , termed SARS-CoV-X. We show that sera from patients with different COVID-19 immunological histories possess cross-neutralising antibodies against the spike (S) protein of multiple zoonotic sarbecoviruses . Mathematical simulations using these viruses show a significant reduction in their likelihood of emergence in populations with current levels of SARS-CoV-2 natural and vaccine-derived immunity, with the outcome determined by the extent of cross-protection and the R_0 of the novel virus. We also show that preventative vaccination programs agains...

#Validation of #H5 #influenza virus subtyping #RTqPCR #assay and low prevalence of H5 #detection in 2024-2025 influenza virus season

Abstract A sustained outbreak of H5N1 influenza virus among wild fowl and domestic livestock has caused more than 70 zoonotic infections in humans in the United States , including one death. The Centers for Disease Control and Prevention has recommended rapid H5 subtyping for all hospitalized cases with influenza A virus infection to enable prompt initiation of antiviral treatment , as well as infection prevention and implementation of public health measures to control spread. To address these needs, we developed a multiplex RT-qPCR assay to subtype H5 influenza virus in nasal, nasopharyngeal, and conjunctival specimens with a limit of detection of 230 copies/mL. No cross-reactivity was observed with other common respiratory viruses, including seasonal H3N2 and H1N1 influenza A viruses. We retrospectively subtyped 590 influenza A-positive clinical specimens processed by University of Washington labs between March 2024 and February 2025, including 512 specimens collected during the 2024...

The #epidemiology of #pathogens with #pandemic potential: A review of key parameters and clustering analysis

Abstract Introduction   In the light of the COVID-19 pandemic many countries are trying to widen their pandemic planning from its traditional focus on influenza. However, it is impossible to draw up detailed plans for every pathogen with epidemic potential. We set out to try to simplify this process by reviewing the epidemiology of a range of pathogens with pandemic potential and seeing whether they fall into groups with shared epidemiological traits.  Methods   We reviewed the epidemiological characteristics of 19 different pathogens with pandemic potential (those on the WHO priority list of pathogens, different strains of influenza and Mpox). We extracted data on the proportion of presymptomatic transmission , incubation period , serial interval and basic reproduction number (R0) for the targeted pathogens. We applied unsupervised machine learning (specifically K-means and hierarchical clustering) to categorise these pathogens based on these characteristics.  Resul...

Modelling #practices, #data #provisioning, #sharing and dissemination needs for #pandemic decision-making: a European survey-based modellers’ perspective

Abstract Introduction :  Advanced outbreak analytics played a key role in governmental decision-making as the COVID-19 pandemic challenged health systems globally. This study assessed the evolution of European modelling practices , data usage, gaps, and interactions between modellers and decision-makers to inform future investments in epidemic-intelligence globally.  Methods :  We conducted a two-stage semi-quantitative survey among modellers in a large European epidemic-intelligence consortium. Responses were analysed descriptively across early, mid-, and late-pandemic phases. Policy citations in Overton were used to assess the policy impact of modelling.  Findings :  Our sample included 66 modelling contributions from 11 institutions in four European countries. COVID-19 modeling initially prioritised understanding epidemic dynamics. Evaluating non-pharmaceutical interventions and vaccination impacts became equally important in later phases. 'Traditional' surve...

Characterising viral #clearance #kinetics in acute #influenza

Abstract Pharmacometric assessment of antiviral efficacy in acute influenza informs treatment decisions and pandemic preparedness. We assessed natural viral clearance in untreated acute influenza to guide clinical trial design. Standardized duplicate oropharyngeal swabs were collected daily over 14 days from 80 untreated low-risk Thai adults , with viral densities measured using qPCR. We evaluated three models to describe viral clearance: exponential, bi-exponential, and growth-and-decay . The growth-and-decay model provided the best fit, but the exponential decay model was the most parsimonious. The median viral clearance half-life was 10.3 hours (interquartile range [IQR]: 6.8-15.4), varying by influenza type: 9.6 hours (IQR: 6.2-13.0) for influenza A and 14.0 (IQR: 10.3-19.3) hours for influenza B. Simulated trials using clearance parameters from the exponential decay model, showed that 120 patients per arm provide over 90% power to detect treatments accelerating viral clearance by ...

#Antiviral use and the effects of #drug #resistance on the #transmission dynamics of #influenza

Abstract The effectiveness of antivirals in mitigating influenza outbreaks depends on both their ability to reduce the number of infections and the risk of drug resistance. We extended a previously developed mathematical model to investigate the impact of mitigation strategies , including mono or combination antiviral treatment or chemoprophylaxis and vaccination , on influenza transmission dynamics. Our findings indicate that chemoprophylaxis is more effective than treatment in reducing influenza burden, except when the resistant strain has a high transmission rate, in which case chemoprophylaxis may trigger a resistance-driven secondary infection wave. Combination therapy considerably reduces resistance emergence with similar infection numbers as mono-therapy. Vaccination coverage of at least 80% is required to prevent outbreaks; otherwise, antivirals can contribute to outbreak control provided drug resistance emergence is low. This analysis could inform public health decision-making...