ETIDIOH - NEW

  Abstract Limited information is available on the impact of non-pharmaceutical interventions (NPIs) and immune debt on influenza during COVID-19 . This retrospective population-based research examined the effect of the COVID-19 pandemic on the prevalence of influenza-like illness (ILI) cases and influenza positive cases in Sichuan Province . Interrupted time series analysis (ITS) was conducted using data gathered from surveillance hospitals throughout 21 cities , including information on patients diagnosed with ILI and positive nucleic acid testing. Subsequent to the implementation of NPIs, there was a notable temporary reduction in both the incidence of ILI cases and confirmed influenza cases, decreasing by 94.7% and 98.0%, respectively (P<0.001). The weekly trend in influenza-positive cases was notable (+4.1%/week, P=0.001). Following the execution of the second-phase intervention, the fluctuations in the transient changes of ILI patients and influenza-positive cases varied ;...

  Abstract We examined whether the recent emergence of influenza A(H3N2) subclade K, associated with an unusually early influenza season in the Northern hemisphere, was accompanied by a reduction in human population immunity . Using virus neutralisation assays on pre-epidemic human sera collected in May 2025, we found evidence of moderate antigenic drift . Further, vaccines used in the 2024/2025 season induced cross-neutralising immunity . These findings provide timely insight for interpreting recent influenza epidemiology and informing vaccine strain selection. Competing Interest Statement The following authors declare no conflict of interests: KD, RI, LM, SR, HC, GGA, MSA, VS, ZW, SKW, JZ, BJW, DLR, JH, OML, JG, CJRI. PRM receives funding for research work for MSD. EH has received an honorarium for advisory board work for Seqirus. ET has received funding from Novavax and Astra Zeneca. Funding Statement This work was funded by the Medical Research Council (MRC) to the MRC-Universi...

  Abstract Background :  Chikungunya virus (CHIKV) has historically been regarded as a low-fatality infection ; however, growing evidence from diverse study designs demonstrated a substantial mortality burden during large-scale epidemics. In 2025, Réunion Island experienced a major CHIKV outbreak , raising renewed concerns about its fatal impact.  Methods :  We conducted an ecological time-series analysis of all-cause mortality during the 2025 chikungunya epidemic. Expected deaths were estimated using two complementary approaches: (i) a baseline based on age-specific mean mortality rates from the same calendar months in the post-pandemic period and (ii) long-term Poisson regression models using a log-link function and population offset, excluding the COVID-19 pandemic period. Excess mortality was calculated as the difference between observed and expected deaths during periods when observed mortality significantly exceeded the upper bound of the 95% confidence interva...

  Abstract The risk of highly pathogenic avian influenza infection to humans is challenging to estimate because many human avian influenza virus (AIV) infections are undetected as they may be asymptomatic , symptomatic but not tested , and as contact tracing is difficult because human-to-human spread is rare. We derive equations that consider the evolutionary mechanisms that give rise to pandemics and are parameterized to be consistent with records of past pandemics. We estimate that thousands of human AIV infections occur worldwide in an average year and estimate the infection fatality ratio as 32 deaths per 10,000 infections (95% confidence interval: [9.6, 75]). We estimate that preventing 20% of animal-to-human influenza spillovers annually would delay pandemic emergence by an average of 9.4 years . There is a high level of uncertainty in our estimates due to the few records of past pandemics, but even so this infection fatality ratio is comparable to SARS-CoV-2 during the recen...

  Abstract Since early-2024 unprecedented outbreaks of highly pathogenic avian influenza H5N1 clade 2.3.4.4b have been ongoing in dairy cattle in the United States with significant consequences for the dairy industry and public health . Estimation of key epidemiological parameters is required to support outbreak response , including predicting the likely effectiveness of interventions and testing strategies . Here, we pool limited publicly available data from four studies of naturally and experimentally infected dairy cattle. We quantify Ct value trajectories of infected dairy cattle and the relationship between Ct value and the log-titer of infectious virus , a proxy for infectiousness . We estimate that following infection minimum Ct values are rapidly reached within 1–2 days with a population mean Ct value of 15.7 (12.9, 18.4). We identify a threshold Ct value of 21.8 (19.9, 24.6), with values of Ct value above this threshold representing little-to-no infectious viral load . Fin...

  Summary Background Lassa virus (LASV) is a persistent threat to public health in west Africa and beyond . LASV is endemic in west Africa and each year it is responsible for an estimated 2·7 million infections, 23 700 hospitalisations, and 5000 deaths . With over 32 reported cases of Lassa fever imported into non-endemic countries—one-third of which were fatal—the importance of enhanced detection and management of Lassa fever extends beyond west Africa. Methods The prevalence, pathogenesis, and persistence (PREPARE) study was a prospective cohort study among patients admitted to two hospitals in a hyperendemic area of Liberia . Any patients aged 5 years or older with a febrile illness were eligible to enrol and be tested for Lassa fever. The study aimed to measure the prevalence of LASV infection and assess the signs and symptoms, LASV viral replication kinetics, and LASV-specific IgM and IgG responses longitudinally among adults and children with laboratory-confirmed Lassa fever....

  Summary Background Cancer is a leading cause of death globally. Accurate cancer burden information is crucial for policy planning , but many countries do not have up-to-date cancer surveillance data. To inform global cancer-control efforts, we used the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023 framework to generate and analyse estimates of cancer burden for 47 cancer types or groupings by age, sex, and 204 countries and territories from 1990 to 2023, cancer burden attributable to selected risk factors from 1990 to 2023, and forecasted cancer burden up to 2050. Methods Cancer estimation in GBD 2023 used data from population-based cancer registration systems , vital registration systems, and verbal autopsies. Cancer mortality was estimated using ensemble models , with incidence informed by mortality estimates and mortality-to-incidence ratios (MIRs). Prevalence estimates were generated from modelled survival estimates, then multiplied by disability weig...

  Highlights •  Middle East respiratory syndrome-coronavirus was first detected in 2012 in Saudi Arabia. •  Since 2012, Middle East respiratory syndrome caused 2626 confirmed cases. •  20% of cases involve contact with dromedary camels or their products. •  Human-to-human spread occurs, mainly in healthcare settings. •  A case fatality rate is 36-40%. Source: IJID Regions,  https://www.sciencedirect.com/science/article/pii/S2772707625001663?via%3Dihub ____

  Abstract Background Ebola virus disease (EVD) is a severe and often fatal illness with high transmission potential and recurring outbreaks . Traditional compartmental models often neglect biologically important delays , such as the latent period before an infected individual becomes infectious, limiting their ability to capture real-world epidemic patterns. Including such delays can provide a more accurate understanding of outbreak persistence and control strategies. Methods In this study, we develop and analyze a novel deterministic SIRR model that captures the complex transmission dynamics of Ebola by explicitly combining nonlinear incidence rates with a delay differential equation framework . Unlike traditional models, this approach integrates a biologically motivated delay to represent the latent period before infectiousness, providing a more realistic depiction of disease spread. The basic reproduction number (R0) is derived using the next-generation matrix, and local stabil...

  Abstract This study compares infant (0–24 months) respiratory infection presentations to a Northern Italian paediatric emergency department across two post-pandemic winters ( 2022–2023 vs 2023–2024 ). Despite an approximate 44% reduction in visits in 2023–2024 (N=176 in 2023–2024 vs N=317 in 2022–2023), infants in the 2023–2024 season experienced significantly higher proportions of ventilatory support (51.1% vs 32.8%, p<0.001) and intensive care unit admission (15.9% vs 1.9%, p<0.001) than those presenting in 2022–2023, with a non-significant trend towards higher hospitalisation (88.1% vs 81.7%, p=0.052). Respiratory syncytial virus re-emerged as the dominant pathogen (43.2% vs 27.7%, p<0.001) in 2023–2024, alongside increased human metapneumovirus and influenza A H1N1 . These findings highlight a concerning shift towards increased severity, underscoring the need for ongoing surveillance. Source: BMJ Paediatric Open,  https://bmjpaedsopen.bmj.com/content/9/1/e003695...

Abstract Since late 2021, a panzootic of highly pathogenic H5N1 avian influenza virus has driven significant morbidity and mortality in wild birds, domestic poultry, and mammals. In North America , infections in novel avian and mammalian species suggest the potential for changing ecology and establishment of new animal reservoirs . Outbreaks among domestic birds have persisted despite aggressive culling, necessitating a re-examination of how these outbreaks were sparked and maintained. To recover how these viruses were introduced and disseminated in North America, we analyzed 1,818 Hemagglutinin (HA) gene sequences sampled from North American wild birds, domestic birds and mammals from November 2021-September 2023 using Bayesian phylodynamic approaches. Using HA, we infer that the North American panzootic was driven by ~8 independent introductions into North America via the Atlantic and Pacific Flyways, followed by rapid dissemination westward via wild, migratory birds. Transmission wa...

  Abstract Background   The ongoing H5N1 panzootic in mammals has amplified zoonotic pathways to facilitate human infection . Characterising key epidemiological parameters for H5N1 is critical should it become widespread.  Aim   To identify and estimate critical epidemiological parameters for H5N1 from past and current outbreaks, and to compare their characteristics with human influenza subtypes and the 2003 Netherlands H7N7 outbreak.  Methods   We searched PubMed, Embase, and Cochrane Library for systematic reviews reporting parameter estimates from primary data or meta-analyses. To address gaps, we searched PubMed and Google Scholar for studies of any design providing relevant estimates. We estimated the basic reproduction number for the recent outbreak in the United States (US) and the 2003 Netherlands H7N7 outbreak. In addition we estimated the serial interval for H5N1 using data from previous household clusters in Indonesia. We also applied a branching...

  Abstract Reassortment between different influenza strains occurs when they co-infect the same host cell . The emergence of a reassortant virus depends on both its intrinsic fitness and extrinsic factors , including pre-existing humoral immunity . The generation of pandemic strains , such as H2N2 and H3N2 , and zoonotic influenza A viruses, like H5N6, H5N8, and H7N9 , in birds is suggested to be the result of extensive selection by pre-existing antibodies . To further explore the role of humoral immunity in reassortment , we generated two divergent fluorescent protein-expressing viruses and used strain-specific and cross-reactive monoclonal antibodies (mAbs) to assess the impact of cross-immunity on reassortment. Our results indicate that all mAbs altered the genotypic diversity and significantly reduced the release of progeny virions in co-infected cells both in vitro and in vivo. Moreover, antibody transfer studies in mice revealed protection from challenge with divergent pathog...

Summary Background Identifying measles transmission patterns and the most susceptible populations is crucial for anticipating and preventing outbreaks . The aim of this study was to assess the current epidemiology of measles in Italy to provide key metrics to anticipate and prevent future transmission risks. Methods In this epidemiological assessment study , we analysed measles epidemiological data from the National Integrated Measles and Rubella Surveillance System coordinated by the Department of Infectious Diseases of the Istituto Superiore di Sanità in Italy from Jan 1, 2013, to Dec 31, 2022. We analysed individual case records to assess the proportion of transmission that occurred in different settings; we also used pairs of measles cases to estimate the generation time and the proportion of transmission episodes between population groups defined by age and vaccination status. All suspected cases meeting the measles case definition were included in our analysis. Data, complemented...

Abstract The highly pathogenic avian influenza (HPAI) subtype H5N1 is a severe viral disease which continues to pose a significant threat to public health and a rigorous understanding of its transmission dynamics across its major pathways is essential for developing effective control strategies . Phylogenetic analysis suggests that H5N1 spillover occurs primarily between wild and domestic birds . However, increasing contact between these species and humans increases the risk of zoonotic transmission . In this work, we develop a mathematical model to examine the transmission dynamics of H5N1 and evaluate the effectiveness of proposed control measures. The model employs a compartmental framework that includes human, domestic, and wild bird populations. We then use this model to estimate the basic reproduction number for each population group and perform a sensitivity analysis to assess the contribution of the parameters to the spread of the disease. Numerical simulations are also conduct...

Abstract Avian influenza is a highly contagious viral disease that affects both domestic and wild birds , with occasional spillover to mammals , including humans. As of June 2025, 117 H5N1 infections in humans have been reported worldwide since 2020. Given the ability of the virus to infect mammals, there is a growing concern about its potential for human-to-human transmission . Currently, contact tracing and self-isolation are used in the UK to manage contacts of confirmed human cases of avian influenza. In this study, we aimed to estimate potential outbreak sizes and evaluate the effectiveness of contact tracing and self-isolation in managing avian influenza spillover events. We used a novel dataset from the Avian Contact Study to analyse contact patterns within an agricultural population at high risk of avian influenza exposure through contact with birds. We modelled outbreak sizes using a stochastic branching process model with measured contact data. Most simulations resulted in sm...

Summary Background Clade I monkeypox virus is endemic in DR Congo. We aim to describe the epidemiological trends of the cocirculating subclades Ia and Ib mpox outbreaks in Kinshasa, DR Congo. Methods This retrospective observational study included suspected and laboratory-confirmed mpox cases reported between Jan 1, 2023, and Oct 31, 2024, in Kinshasa. Skin lesion swabs or blood samples were collected as part of a routine countrywide mpox surveillance programme. To confirm the diagnosis of mpox, all samples were tested at the Institut National de Recherche Biomédicale (INRB) using real-time PCR. Whole-genome sequencing was conducted for phylogenomic analysis and assessment of APOBEC3 type mutations. Samples that remained unassigned to subclade Ia or Ib after whole-genome sequencing and real-time PCR were labelled as an unknown subclade. Findings As part of routine disease surveillance, 1479 suspected mpox cases were reported in Kinshasa. Samples were collected from 1314 suspected mpox ...

Abstract Influenza A viruses (IAVs) are prime examples of emerging viruses in humans and animals. IAV circulation in domestic animals poses a pandemic risk as it provides new opportunities for zoonotic infections. The recent emergence of H5N1 IAV in cows and subsequent spread over multiple states within the USA, together with reports of spillover infections in humans, cats and mice highlight this issue. The horse is a domestic animal in which an avian-origin IAV lineage has been circulating for >60 years . In 2018/19, a Florida Clade 1 (FC1) virus triggered one of the largest epizootics recorded in the UK , which led to the replacement of the Equine Influenza Virus (EIV) Florida Clade 2 (FC2) lineage that had been circulating in the country since 2003. We integrated geographical, epidemiological, and virus genetic data to determine the virological and ecological factors leading to this epizootic. By combining newly-sequenced EIV complete genomes derived from UK outbreaks with existi...

Abstract Background .  Sudan virus (SUDV) has caused multiple outbreaks in Uganda over the past two decades, leading to significant morbidity and mortality . The recent outbreaks in 2022 and 2025 highlight the ongoing threat posed by SUDV and the challenges in its containment. This study aims to characterize the epidemiological patterns and phylogenomic evolution of SUDV outbreaks in Uganda, identifying key factors influencing transmission and disease severity.  Methods .  We conducted a retrospective observational study analyzing epidemiological and genomic data from SUDV outbreaks in Uganda between 2000 and 2025. Epidemiological data were collected from official sources, including the Ugandan Ministry of Health and the World Health Organization, supplemented with reports from public health organizations. Genomic sequences of SUDV were analyzed to investigate viral evolution and identify genetic variations associated with pathogenicity and transmissibility.  Results...

Abstract Determining the incubation period of Oropouche virus disease can inform clinical and public health practice . We analyzed data from 97 travel-associated cases identified by the Centers for Disease Control and Prevention (n = 74) or the GeoSentinel Network (n = 13) and 10 cases from published literature . Using log-normal interval-censored survival analysis, we estimated the median incubation period to be 3.2 (95% CI 2.5–3.9) days . Symptoms developed by 1.1 (95% CI 0.6–1.5) days for 5% of patients, 9.7 (95% CI 6.9–12.5) days for 95% of patients, and 15.4 (95% CI 9.6–21.3) days for 99% of patients . The estimated incubation period range of 1–10 days can be used to assess timing and potential source of exposure in patients with Oropouche symptoms. For patients with symptom onset >2 weeks after travel , clinicians and public health responders should consider the possibility of local vectorborne transmission or alternative modes of transmission. Source: US Centers for Disease C...