ETIDIOH - NEW

At a glance -- The Influenza Risk Assessment Tool (IRAT) is a CDC evaluation tool developed with assistance from global animal and human health influenza experts. -- The IRAT is used to assess the potential pandemic risk of influenza A viruses that are not currently circulating in people. -- This latest IRAT assessed two recent clade 2.3.4.4b avian influenza A(H5N1) viruses: A/California/147/2024 and A/Washington/239/2024. -- These viruses scored in the "moderate risk" category for potential emergence and public health impact , similar to previous assessments of earlier clade 2.3.4.4b avian influenza A(H5N1) viruses. These results validate the proactive, coordinated U.S. government response. -- The IRAT does not assess the immediate risk to the public's health, which is unchanged and remains low, and it does not predict future pandemics. Purpose The IRAT uses expert opinion to evaluate the potential of a representative novel influenza A virus to gain the ability for perso...

{Excerpt} Time Period: April 20, 2025 - April 26, 2025 - H5 Detection :  5 sites ( 1.2% ) - No Detection :  402 sites ( 98.8% ) - No samples in last week :  91 sites (...) Source: US Centers for Disease Control and Prevention,  https://www.cdc.gov/bird-flu/h5-monitoring/index.html ____

Abstract Highly pathogenic avian influenza (HPAI) clade 2.3.4.4b H5N1 is circulating widely in lactating cows in the United States . Due to the critical need for intervention strategies for this outbreak, we evaluated antibody and cellular immune responses of a clade 2.3.4.4b H5 mRNA-LNP vaccine in calves . We found that the H5 mRNA-LNP vaccine induced a robust antibody and CD8+ T cellular-mediated immune response and conferred protection against clade 2.3.4.4b H5N1 infection. Source: BioRxIV,  https://www.biorxiv.org/content/10.1101/2025.05.01.651548v1 ____

Abstract Highly pathogenic avian influenza (HPAI) represents a threat to animal and human health , with the ongoing H5N1 outbreak within the H5 2.3.4.4b clade being the largest on record. However, it remains unclear what factors have contributed to its intercontinental spread . We use Bayesian additive regression trees, a machine learning method designed for probabilistic modelling of complex nonlinear phenomena, to construct species distribution models (SDMs) for HPAI clade 2.3.4.4b presence. We identify factors driving geospatial patterns of infection and project risk distributions across Europe . Our models are time-stratified to capture both seasonal changes in risk and shifts in epidemiology associated with the succession of H5N6/H5N8 by H5N1 within the clade . While previous studies aimed to model HPAI presence from physical geography, we explicitly consider wild bird ecology by including estimates of bird species richness, abundance of specific taxa, and "abundance indices...

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...

ABSTRACT The outbreak of H5N1 in dairy cattle in United States revealed challenges in identification and management of a novel disease . The virus showed an exceptional ability to spread between farms and among cows within a farm. The impact of the virus on dairy cattle varied from nonclinical to severe clinical signs and death. Many dairy producers did not report clinical signs in their cows or test for the virus. Cats and peridomestic birds on many affected dairies died from viral exposure . Dairy workers showed signs of conjunctivitis , which was confirmed to be due to H5N1. With the disease affecting multiple species and showing efficient cow-to-cow transmission , the situation only worsened. There was a negative impact on the relationships among dairy producers, dairy workers, poultry producers, and veterinarians, in which professional and personal relationships were severed and some experienced loss of employment. The regulatory response varied by geographic location, and in some...

Abstract {1} The 2023–24 epidemic of Oropouche fever in the Americas and the associated ongoing outbreak in Cuba suggests a potential state shift in the epidemiology of the disease , raising questions about which vectors are driving transmission. In this study, we conduct a systematic review of vector competence experiments with Oropouche virus (OROV, Orthobunyavirus ) that were published prior to the 2023–24 epidemic season. Only seven studies were published by September 2024, highlighting the chronic neglect that Oropouche virus (like many other orthobunyaviruses) has been subjected to since its discovery in 1954. Two species of midge (Culicoides paraensis and C. sonorensis) consistently demonstrate a high competence to transmit OROV (~30%), while mosquitoes (including both Aedes and Culex spp .) exhibited an infection rate consistently below ~20%, and showed limited OROV transmission . Further research is needed to establish which vectors are involved in the ongoing outbreak in Cub...

Abstract Despite accumulating evidence that bat-derived coronaviruses often require intermediate hosts to facilitate transmission to humans1, the potential role of fur animals in zoonotic coronavirus spillovers has largely been overlooked2. Here we report the isolation and characterization of a novel mink respiratory coronavirus (MRCoV) from farmed minks with pneumonia . Notably, MRCoV uses angiotensin-converting enzyme 2 (ACE2) as a receptor and can infect mink, bat, monkey, and human cells . Cryo-electron microscopy analysis revealed that the MRCoV receptor-binding domain (RBD) binds to the same interface on ACE2 receptors as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RBD , despite exhibiting notable structural differences. We identify the key determinants on ACE2 and MRCoV RBD that confer efficient binding. HKU5-33S, a bat coronavirus closely related to MRCoV , utilizes ACE2 of bat Pipistrellus abramus and requires only two amino acid substitutions to adapt to mink...

 Two wild servals in Dhaka Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6453 ____

Abstract The relationship among timing and severity of COVID-19 during pregnancy , placental pathology , and adverse pregnancy outcomes is not well understood. A prospective cohort study of 497 pregnant patients with COVID-19 whose placentas underwent systematic pathologic examination was conducted. The main exposure was timing of COVID-19 during pregnancy (first/second versus third trimester). The primary outcome was composite placental pathology that included high grade maternal vascular malperfusion or greater than 25 percent perivillous fibrin deposition. There were 63 patients who had the composite placental pathology outcome. In adjusted analyses that controlled for maternal age, parity, active infection at delivery, interval from time of diagnosis to delivery and COVID-19 variant, timing of COVID-19 during pregnancy was not associated with risk of the composite placental pathology outcome . Among secondary COVID-19 related exposures that were investigated, severity of disease an...

Abstract Swine Influenza A Virus (IAV-S) poses a significant burden to both the pork industry and public health . Current vaccines against IAV-S are infrequently updated and induce strain-specific immunity. Computational platforms have recently emerged as a promising strategy to develop new-age vaccines. Here, we describe the Epigraph , a computationally derived and epitope optimized set of vaccine immunogens. When compared to wildtype immunogens (WT) and a commercial comparator (FluSure XP®), pigs immunized with Epigraph demonstrate significantly improved breadth and magnitude of antibody responses . Further, pigs immunized with Epigraph show more robust and a wider breadth of cross-reactive cell-mediated immune responses than pigs immunized with WT immunogens. In an experimental infection model , Epigraph immunized pigs demonstrate a significant reduction of clinical disease, lower shedding of infectious virus, reduction of lung lesions, and lower microscopic immunopathology compared...

Abstract Highly Pathogenic Avian Influenza (HPAI) is a prominent candidate for a future human pandemic arising from a zoonotic spillover event . Its best-known strain is H5N1 , with South- or South-East Asia a likely location for an initial outbreak. Such an outbreak would be initiated through a primary event of bird-to-human infection, followed by sustained human-to-human transmission . Early interventions would require the extraction, integration and interpretation of epidemiological information from the limited and noisy case data available at outbreak onset. We studied the implications of a potential zoonotic spillover of H5N1 influenza into humans. Our simulations used BharatSim , an agent-based model framework designed primarily for the population of India , but which can be tuned easily for others. We considered a synthetic population representing farm-workers (primary contacts) in a farm with infected birds. These primary contacts transfer infections to secondary (household) co...

Abstract Surveillance of influenza A viruses in pigs (SwIAV) is critical for identification of novel genetic groups that pose a risk to pig health and might have zoonotic potential . SwIAVs circulating in pigs in England between 2014 and 2021 were characterised using whole genome sequencing (WGS). Haemagglutinin (HA) and neuraminidase (NA) sequencing data from 82 of 368 influenza A positive samples (71 submissions) were determined, identifying H1N1 and H1N2 subtypes from the 1A classical swine and 1B human-seasonal lineages respectively. The 1B lineage viruses were predominant, accounting for 68.29% of sequenced viruses, with 1A lineage viruses comprising 31.71%, primarily from the 1A.3.3.2 clade (2009 H1N1 pandemic origin). This study characterised previously undefined diversity within the 1B lineage which led to the designation of new HA clades 1B.1.1.1, 1B.1.1.2 and 1B.1.1.3. Complete genome data were obtained from 64/82 viruses thereby updating the definition of genetic diversity t...

Abstract This test-negative case-control study within the US Veterans Affairs Healthcare System aims to estimate early vaccine effectiveness (VE) of the BNT162b2 KP.2 vaccine (2024–2025 formulation) compared to not receiving the KP.2 vaccine against COVID-19 outcomes. The study includes adult patients (age ≥18 years) with an acute respiratory infection (ARI) in hospital, emergency department and urgent care (ED/UC), or outpatient settings between September 5 and November 30, 2024. Separate multivariable logistic regression models compare the odds of receiving BNT162b2 KP.2 vaccine among SARS-CoV-2 positive cases and test-negative controls within each ARI outcome category, while adjusting for potentially confounding variables. Among 44,598 ARI episodes, VE is 68% (42–82%), 57% (46–65%), and 56% (36–69%) against COVID-19 -associated hospitalizations, emergency department and urgent care visits , and outpatient visits, respectively. Uptake of updated COVID-19 vaccines is low (3.7%). Sourc...

Abstract Immunisation remains the most cost-effective mechanism to combat global influenza infection and is widely employed against seasonal influenza viruses. Zoonotic transmission of avian influenza A viruses represents a significant threat to human health given the lack of population level immunity , which could translate into an influenza pandemic . Therefore, there is a need to better understand pre-existing human immunity against avian influenza strains. as highlighted by the recent rapid, global spread of avian H5Nx clade 2.3.4.4b variants. Here, we sought to quantify the frequencies and specificities of B cells recognising avian hemagglutinin (HA) within unexposed adults , and to characterise the ability of seasonal immunisation to boost cross-reactive immune responses to H5Nx strains, including from clade 2.3.4.4b. Low but detectable serum antibody titres against H5 and H7 avian influenza HA were observed in donors. The frequency of memory B cells with cross-reactive recogniti...

Abstract Influenza A(H7N9) virus showed high pathogenicity in humans when it emerged in 2013. Cigarette smoke (CS) causes pulmonary diseases including bronchitis, emphysema, and lung cancer . Although habitual smoking is thought to increase the risk of severe seasonal influenza virus infection, its effect on A(H7N9) virus infection is poorly understood . Here, we employed a mouse model of long-term exposure to CS to investigate the effect of CS on the pathogenicity of A(H7N9) virus infection. Unexpectedly, body weight loss for mice exposed to CS was milder than that for mock-treated mice upon A(H7N9) virus infection. CS exposure improved the survival rate of A(H7N9) virus-infected mice even though virus titers and pathological changes in the lungs were not significantly different between CS-exposed and control mice. Microarray analysis showed that CS-exposure activates cytokine/chemokine activity , immune response, and cell cycle activities that resemble reactivities against A(H7N9) vi...

{Excerpt} Situation at a glance As of 18 April 2025, a total of 2318 measles cases , including three deaths , have been confirmed in six countries in the WHO Region of the Americas , an 11-fold increase compared to the same period in 2024 .  The majority of cases have occurred among people between 1 to 29 years , who are either unvaccinated or have an unknown vaccination status .  Additionally, most cases are imported or linked to importation.  Measles is a highly contagious, airborne viral disease that can lead to severe complications and death.  Although it is preventable with two doses of the vaccine, over 22 million children worldwide did not receive their first dose of the vaccine in 2023. This has contributed to a global rise in measles cases in 2024, which heightens the risk of imported infections, particularly from unvaccinated travellers arriving from areas where the virus is actively circulating.  WHO is working closely with countries in the WHO Region...

 A Red Fox in Tromso Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6450 ____

Abstract Educational farms provide students with hands-on experience in agricultural and animal practices . However, the close contact between humans and farm animals creates a significant interface for zoonotic disease transmission , yet research on infectious diseases in such settings remains limited. This study investigates the ongoing spillovers of human-origin influenza A virus (IAV) into swine at an educational farm in central Chile , describing IAV prevalence, outbreak dynamics, and the genomic characterization of detected strains. The Menesianos educational farm, located in Melipilla, central Chile, houses approximately 40 swine alongside other domestic animals , such as horses and cows . As part of an active IAV surveillance project, monthly nasal swab samples were collected from pigs between June 2019 and September 2023 for IAV detection via RT-qPCR targeting the M gene, with positive samples subsequently sequenced. During the study period, monthly IAV prevalence ranged from ...

Abstract Highly Pathogenic Avian Influenza A/H5N1 Virus has been found in multiple US states since 2024. While human infection risk is currently low, children are a high-risk group for severe infection as the virus evolves. Preventive efforts should prioritize children in vaccine and therapeutic clinical trials and vaccine implementation strategies. Source: Journal of Pediatric Infectious Diseases Society,  https://academic.oup.com/jpids/advance-article-abstract/doi/10.1093/jpids/piaf035/8120791?redirectedFrom=fulltext ____