#Poland - High pathogenicity avian #influenza #H5N1 viruses (Inf. with) (#poultry) - Immediate notification

 

A breeding chickens farm in Śląskie Region.

Source: 

Link: https://wahis.woah.org/#/in-review/7243

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#Portugal - #Influenza A #H5N6 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification [FINAL]

 

Di Jiyang Chen - Opera propria, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15507046

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This event was created to allow the recreation of outbreak ob_164520, previously reported as H5N1 subtype.

Subadult unspecified seagull. In the Portuguese Exclusive Economic Zone. 

Source: 

Link: https://wahis.woah.org/#/in-review/7234

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The effect of #NPIs on #influenza throughout the #COVID19 #pandemic: an 8-year interrupted time series study

 

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; nonetheless, both subsequently exhibited a significant declining trend (P<0.001). Temperature had a substantial negative correlation with both indicators (P<0.001), resulting in a reduction of instances by 13.0% and 11.5%, respectively; humidity demonstrated no statistically significant impact on either. Our data demonstrate that NPIs significantly reduce two influenza outcome indicators in the short term; nevertheless, they do not effectuate a sustainable alteration in the long-term increasing trend of influenza. Through the examination of the dynamic effects of NPIs on influenza transmission, we provide policymakers with an enhanced evaluative instrument, a decision-making framework, and theoretical backing, while also contemplating the prospective advantages and hazards of NPIs for additional respiratory infectious diseases in the future.

Source: 

Link: https://www.nature.com/articles/s41598-026-37911-2

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Subclade K #influenza A #H3N2 viruses display partial immune #escape with preserved cross-neutralisation in a #UK population

 

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-University of Glasgow Centre for Virus Research (grants MC_UU_0034/1, MC_UU_0034/2, MC_UU0034/3, MC_UU0034/5 and MC_UU0034/6). Funding to EH and PRM from the Medical Research Council (MRC) and Department for Environment, Food and Rural Affairs (Defra, UK) as FluTrailMap-One Health [MR/Y03368X/1] is also acknowledged.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2026.01.27.26344933v1

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A lethal mouse #model of #Oz virus #infection reveals hepatic involvement and enables evaluation of #antiviral and #vaccine efficacy

 

Abstract

Oz virus (OZV), a member of the genus Thogotovirus in the family Orthomyxoviridae, is an emerging tick-borne virus reported in Japan. A fatal human case and seroepidemiological evidence of widespread exposure among wild animals and humans suggest its potential public health significance. However, no animal models suitable for pathogenic studies or evaluation of countermeasures are available for OZV. Here, we have established a lethal mouse model of OZV infection using cell-adapted virus and mice lacking type I interferon signaling (B6 Ifnar1 KO mice). OZV infection resulted in 100% mortality and was characterized by robust viral replication in the liver and spleen, severe hepatitis, and acute liver injury. Using this model, we also demonstrated that oral administration of T-705, an antiviral drug widely used against RNA viruses, as well as immunization with an inactivated whole virus particle vaccine, protected B6 Ifnar1 KO mice from lethal OZV infection by mitigating the acute hepatitis. The present study provides critical insights into OZV pathogenesis and establishes a practical in vivo platform for the development of countermeasures against OZV infection.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

Japan Society for the Promotion of Science, 25K18810, 25K09431

Japan Agency for Medical Research and Development, JP223fa627005, JP24wm0225044

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.01.29.702403v1

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#Hungary - High pathogenicity avian #influenza #H5N1 viruses (Inf. with) (#poultry) - Immediate notification

 

A foie gras goose holding in Jász-Nagykun-Szolnok Region.

Source: 

Link: https://wahis.woah.org/#/in-review/7237

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Increased #Mortality Rates During the 2025 #Chikungunya #Epidemic in #Réunion Island

 

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 interval. 

Results: 

Observed mortality exceeded the upper 95% confidence interval (CI) limit for three consecutive months, coinciding with the epidemic curve and resulting in an estimated 208 excess deaths. These deaths were concentrated among older adults, peaking in April 2025 with a mortality rate ratio of 1.34 (95% CI: 1.22–1.47; p < 0.001). Among older adults, the age-specific excess mortality rate reached 145.3 per 100,000 (95% CI: 125.5–165.0) with a case fatality rate (CFR) of 2.4%, resulting in an overall population excess mortality rate of 23.2 per 100,000 and a total CFR of 0.4%. The number of deaths identified through routine surveillance was substantially lower than our estimates, highlighting a significant discrepancy between reported and excess chikungunya-associated mortality. 

Conclusions: 

Chikungunya epidemics are consistently associated with substantial underrecognized mortality worldwide. Routine surveillance relying solely on laboratory confirmation underestimates the true burden of the disease. Integrating excess mortality analysis, strengthening diagnostic and postmortem investigations, and implementing timely mitigation measures are essential to accurately assess and reduce preventable deaths during future CHIKV outbreaks.

Source: 

Link: https://www.mdpi.com/1999-4915/18/2/180

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#Development of pre-pandemic #influenza candidate #vaccine viruses for use in vaccine manufacturing

 

Abstract

Influenza A viruses continually pose pandemic threats, underscoring the need for timely development of Candidate Vaccine Viruses (CVVs) that meet regulatory expectations for vaccine manufacturing. This protocol describes the procedures used at CDC to generate recombinant CVVs through reverse genetics in accordance with World Health Organization guidelines and CDC’s internal Quality System Requirements (QSR)1,2,3. The QSR incorporates relevant principles from the FDA’s Good Manufacturing Practice (GMP) and Good Laboratory Practice (GLP) regulations, providing a structured framework that ensures documentation integrity, material traceability, and quality oversight during all stages of CVV development. The protocol provides detailed steps for plasmid preparation, virus rescue in Vero cells, and amplification in embryonated chicken eggs, and outlines characterization assays used to confirm the suitability and safety attributes of each CVV. This standardized, quality-driven workflow has supported multiple regulatory submissions and facilitated the transition from CVV development to vaccine manufacturing, strengthening pandemic preparedness.

Source: 

Link: https://www.nature.com/articles/s41541-026-01384-1

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#PB1 #mutations as key #drivers of #influenza A virus #evolution

 

Abstract

Influenza A virus (IAV) is a zoonotic pathogen with a broad host range, posing an ongoing threat to global public health. As the core subunit of the IAV polymerase, polymerase basic protein 1 (PB1) is essential for viral replication and transcription, and its mutations are key drivers of viral evolution. This review evaluates the impact of PB1 mutations on IAV evolution, with a focus on polymerase activity, host adaptation, transmissibility, and virulence. Additionally, it discusses the implications of these mutations for vaccine development. The review aims to provide insights that can inform influenza surveillance, identify novel antiviral targets, and guide vaccine design.

Source: 

Link: https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1768665/full

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#Pathology of dose dependent inocula of #H5N8 avian #influenza viruses in experimentally infected #chicken

 

Abstract

In the present study, we assessed the pathogenicity of H5N8 avian influenza viruses belongs to the clade 2.3.4.4b in chicken. Birds of three different dose groups, 10 2 , 10 4 , and 10 6 EID 50 were used in the study. No mortality was observed in 10 2 EID0 group. Percent cumulative mortality of 10 4 and 10 6 EID 50 group was 66.67 and 100 %, respectively. Varying duration of MDT of 3.2 and 2 days was observed in 10 4 and 10 6 EID 50 group, respectively. The CID 50 of virus was found to be 10 4.5 EID 50 . High no. of viral RNA copies were found both in oropharyngeal and cloacal swabs and in various organs of birds infected in 10 4 and 10 6 EID 50 group. Significant gross and histological changes and presence of viral antigen in various organs were observed in 10 4 and 10 6 EID 50 group. So, the study concludes that Indian HPAI, H5N8 isolates are highly pathogenic in nature to chicken by affecting most organs systemically. CID 50 of this H5N8 virus indicates poor adaption in chicken and it implies poor transmission possibility of this virus for host species in field condition. Though this virus are highly pathogenic in nature as that of HPAI, H5N1 viruses, absence of endothelial staining in most organs attributes variation in replication process and pathogenesis from HPAI, H5N1 viruses. Hence, further studies need to be done to elucidate the pathobiology of this virus in various bird species.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

Indian Council of Agricultural Research, https://ror.org/04fw54a43

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.01.27.700741v1

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Protective #efficacy of a genetically modified attenuated #vaccinia virus #Tiantan strain against #monkeypox virus challenge in a small animal #model

 

ABSTRACT

Vaccinia virus (VACV) confers cross-protective immunity against monkeypox virus (MPXV), the causative agent of mpox, and has therefore been extensively exploited as a preventive vaccine. VACV Tiantan strain (VTT) is a second-generation smallpox vaccine used in China in the last century, and there are consistent efforts to minimize its virulence and ensure its best safety for potential clinical applications. In this study, an attenuated VACV rVTT△C12K2△A45 was constructed by deletion of gene segments related to virulence genes, host range genes, immune regulatory genes, and other functional genes from the VTT genome by genetic engineering. Attenuation characteristics of rVTT△C12K2△A45 were confirmed by smaller plaque size, lower replication capacity in various mammalian cell lines along with tests for neurotoxicity in mice, and lesion formation on rabbit skin. Immunization in BALB/c mice with rVTT△C12K2△A45 induced both anti-MPXV and anti-VACV neutralizing antibodies. Animals vaccinated with rVTT△C12K2△A45 showed lower MPXV viral loads in the lungs and genital organs compared to the non-immunized mice.

Source: 

Link: https://journals.asm.org/doi/full/10.1128/jvi.01843-25?af=R

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#Influenza at the #human - #animal #interface - Summary and #risk #assessment, from 20 December 2025 to 22 January 2026 (#WHO)

 

• New human cases {2}: 

-- From 20 December 2025 to 22 January 2026, based on reporting date, the detection of A(H9N2) in three humans was reported officially. 

• Circulation of influenza viruses with zoonotic potential in animals: 

-- High pathogenicity avian influenza (HPAI) events in poultry and non-poultry animal species continue to be reported to the World Organisation for Animal Health (WOAH).{3} 

-- The Food and Agriculture Organization of the United Nations (FAO) also provides a global update on avian influenza viruses with pandemic potential.{4} 

-- Additionally, low pathogenicity avian influenza viruses as well as swine influenza viruses continue to circulate in animal populations. 

• Risk assessment {5}: 

-- Sustained human to human transmission has not been reported associated with the above-mentioned human infection events. 

-- Based on information available at the time of this risk assessment update, the overall public health risk from currently known influenza A viruses detected at the human-animal interface has not changed and remains low. 

-- The occurrence of sustained human-to-human transmission of these viruses is currently considered unlikely. 

-- Although human infections with viruses of animal origin are infrequent, they are not unexpected at the human-animal interface.  

• IHR compliance {6}: 

-- This includes any influenza A virus that has demonstrated the capacity to infect a human and its haemagglutinin (HA) gene (or protein) is not a mutated form of those, i.e. A(H1) or A(H3), circulating widely in the human population. 

-- Information from these notifications is critical to inform risk assessments for influenza at the human-animal interface.  

Avian influenza viruses in humans 

Current situation:  

-- Since the last risk assessment of 19 December 2025, no new human cases of infection with A(H5) viruses were reported. 

-- According to reports received by WOAH, various influenza A(H5) subtypes continue to be detected in wild and domestic birds in Africa, the Americas, Asia and Europe. 

-- Infections in non-human mammals are also reported, including in marine and land mammals.{7} 

-- A list of bird and mammalian species affected by HPAI A(H5) viruses is maintained by FAO.{8}

A(H9N2), China  

-- Since the last risk assessment of 19 December 2025, China notified WHO of three cases on 6 January 2026. 

-- All cases were children and had mild illnesses, were detected in influenza-like illness (ILI) surveillance, were not hospitalized, and have recovered. 

-- The cases had direct or indirect exposure to poultry or freshly slaughtered poultry. 

-- None of the cases had underlying medical conditions. 

-- No family clusters were reported. 

-- The cases were detected in Hubei, Guangxi and Jiangsu. 

-- Influenza A(H9) viruses were detected in environmental samples collected during the investigations around one of the cases. 

Risk Assessment for avian influenza A(H9N2):  

-- 1. What is the global public health risk of additional human cases of infection with avian influenza A(H9N2) viruses?  

- Most human cases follow exposure to the A(H9N2) virus through contact with infected poultry or contaminated environments. 

- Most human infections of A(H9N2) to date have resulted in mild clinical illness. 

- Since the virus is endemic in poultry in multiple countries in Africa and Asia, additional human cases associated with exposure to infected poultry or contaminated environments are expected but remain unusual. 

- The impact to public health if additional sporadic cases are detected is minimal. 

- The overall global public health risk is low.  

-- 2. What is the likelihood of sustained human-to-human transmission of avian influenza A(H9N2) viruses related to these events?  

- At the present time, no sustained human-to-human transmission has been identified associated with the recently reported human infections with A(H9N2) viruses. 

- Current evidence suggests that A(H9N2) viruses from these cases did not acquire the ability of sustained transmission among humans, therefore sustained human-to-human transmission is thus currently considered unlikely.  

-- 3. What is the likelihood of international spread of avian influenza A(H9N2) virus by travellers?  

- Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. 

- If this were to occur, further community level spread is considered unlikely as current evidence suggests the A(H9N2) virus subtype has not acquired the ability to transmit easily among humans.  

Overall risk management recommendations: 

-- Surveillance and investigations 

• Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global strategic surveillance in animals and humans to detect virologic, epidemiologic and clinical changes associated with circulating influenza viruses that may affect human (or animal) health. Continued vigilance is needed within affected and neighbouring areas to detect infections in animals and humans. Close collaboration with the animal health and environment sectors is essential to understand the extent of the risk of human exposure and to prevent and control the spread of animal influenza. WHO has published guidance on surveillance for human infections with avian influenza A(H5) viruses. 

• As the extent of influenza virus circulation in animals is not clear, epidemiologic and virologic surveillance and the follow-up of suspected human cases should continue systematically. Guidance on investigation of non-seasonal influenza and other emerging acute respiratory diseases has been published on the WHO website. 

• Countries should increase avian influenza surveillance: 

- in domestic and wild birds, 

- enhance surveillance for early detection in cattle populations in countries where HPAI is known to be circulating, include HPAI as a differential diagnosis in non-avian species, including cattle and other livestock populations, with high risk of exposure to HPAI viruses; 

- monitor and investigate cases in non-avian species, including livestock, report cases of HPAI in all animal species, including unusual hosts, to WOAH and other international organizations, share genetic sequences of avian influenza viruses in publicly available databases, implement preventive and early response measures to break the HPAI transmission cycle among animals through movement restrictions of infected livestock holdings and strict biosecurity measures in all holdings, employ good production and hygiene practices when handing animal products, and protect persons in contact with suspected/infected animals.{9} 

- More guidance can be found from WOAH and FAO. 

• When there has been human exposure to a known outbreak of an influenza A virus in domestic poultry, wild birds or other animals – or when there has been an identified human case of infection with such a virus – enhanced surveillance in potentially exposed human populations becomes necessary. Enhanced surveillance should consider the health care seeking behaviour of the population, and could include a range of active and passive health care and/or communitybased approaches, including: 

- enhanced surveillance in local influenza-like illness (ILI)/SARI systems, 

- active screening in hospitals and of groups that may be at higher occupational risk of exposure, and 

- inclusion of other sources such as traditional healers, private practitioners and private diagnostic laboratories. 

• Vigilance for the emergence of novel influenza viruses with pandemic potential should be maintained at all times including during a non-influenza emergency. In the context of the cocirculation of SARS-CoV-2 and influenza viruses, WHO has updated and published practical guidance for integrated surveillance. 

-- Notifying WHO 

• All human infections caused by a new subtype of influenza virus are notifiable under the International Health Regulations (IHR, 2005).{10,11} State Parties to the IHR (2005) are required to immediately notify WHO of any laboratory-confirmed{12} case of a recent human infection caused by an influenza A virus with the potential to cause a pandemic{13}. Evidence of illness is not required for this report. Evidence of illness is not required for this report. 

• WHO published the case definition for human infections with avian influenza A(H5) virus requiring notification under IHR (2005): https://www.who.int/teams/global-influenzaprogramme/avian-influenza/case-definitions. 

-- Virus sharing and risk assessment 

• It is critical that these influenza viruses from animals or from humans are fully characterized in appropriate animal or human health influenza reference laboratories. Under WHO’s Pandemic Influenza Preparedness (PIP) Framework, Member States are expected to share influenza viruses with pandemic potential on a timely basis{14} with a WHO Collaborating Centre for influenza of GISRS. The viruses are used by the public health laboratories to assess the risk of pandemic influenza and to develop candidate vaccine viruses.  

• The Tool for Influenza Pandemic Risk Assessment (TIPRA) provides an in-depth assessment of risk associated with some zoonotic influenza viruses – notably the likelihood of the virus gaining human-to-human transmissibility, and the impact should the virus gain such transmissibility. TIPRA maps relative risk amongst viruses assessed using multiple risk elements. The results of TIPRA complement those of the risk assessment provided here, and those of prior TIPRA risk assessments are published at http://www.who.int/teams/global-influenza-programme/avianinfluenza/tool-for-influenza-pandemic-risk-assessment-(tipra).  

-- Risk reduction 

• Given the observed extent and frequency of avian influenza in poultry, wild birds and some wild and domestic mammals, the public should avoid contact with animals that are sick or dead from unknown causes, including wild animals, and should report dead birds and mammals or request their removal by contacting local wildlife or veterinary authorities.  

• Eggs, poultry meat and other poultry food products should be properly cooked and properly handled during food preparation. Due to the potential health risks to consumers, raw milk should be avoided. WHO advises consuming pasteurized milk. If pasteurized milk isn’t available, heating raw milk until it boils makes it safer for consumption. 

• WHO has published practical interim guidance to reduce the risk of infection in people exposed to avian influenza viruses. 

-- Trade and travellers 

• WHO advises that travellers to countries with known outbreaks of animal influenza should avoid farms, contact with animals in live animal markets, entering areas where animals may be slaughtered, or contact with any surfaces that appear to be contaminated with animal excreta. Travelers should also wash their hands often with soap and water. All individuals should follow good food safety and hygiene practices.  

• WHO does not advise special traveller screening at points of entry or restrictions with regards to the current situation of influenza viruses at the human-animal interface. For recommendations on safe trade in animals and related products from countries affected by these influenza viruses, refer to WOAH guidance.  

-- Links:  

- WHO Human-Animal Interface web page https://www.who.int/teams/global-influenza-programme/avian-influenza 

- WHO Influenza (Avian and other zoonotic) fact sheet https://www.who.int/news-room/fact-sheets/detail/influenza-(avian-and-other-zoonotic) 

- WHO Protocol to investigate non-seasonal influenza and other emerging acute respiratory diseases https://www.who.int/publications/i/item/WHO-WHE-IHM-GIP-2018.2 

- WHO Public health resource pack for countries experiencing outbreaks of influenza in animals:  https://www.who.int/publications/i/item/9789240076884 

- Cumulative Number of Confirmed Human Cases of Avian Influenza A(H5N1) Reported to WHO  https://www.who.int/teams/global-influenza-programme/avian-influenza/avian-a-h5n1-virus 

- Avian Influenza A(H7N9) Information https://www.who.int/teams/global-influenza-programme/avian-influenza/avian-influenza-a-(h7n9)virus 

- World Organisation of Animal Health (WOAH) web page: Avian Influenza  https://www.woah.org/en/home/ 

- Food and Agriculture Organization of the United Nations (FAO) webpage: Avian Influenza https://www.fao.org/animal-health/avian-flu-qa/en/ 

- WOAH/FAO Network of Expertise on Animal Influenza (OFFLU) http://www.offlu.org/ 

___

{1} This summary and assessment covers information confirmed during this period and may include information received outside of this period. 

{2} For epidemiological and virological features of human infections with animal influenza viruses not reported in this assessment, see the reports on human cases of influenza at the human-animal interface published in the Weekly Epidemiological Record here.  

{3} World Organisation for Animal Health (WOAH). Avian influenza. Global situation. Available at: https://www.woah.org/en/disease/avian-influenza/#ui-id-2. 

{4} Food and Agriculture Organization of the United Nations (FAO). Global Avian Influenza Viruses with Zoonotic Potential situation update. Available at: https://www.fao.org/animal-health/situation-updates/global-aiv-withzoonotic-potential. 

{5} World Health Organization (2012). Rapid risk assessment of acute public health events. World Health Organization. Available at: https://iris.who.int/handle/10665/70810. 

{6} World Health Organization. Case definitions for the four diseases requiring notification in all circumstances under the International Health Regulations (2005). Available at: https://www.who.int/publications/m/item/case-definitions-for-the-four-diseases-requiring-notification-towho-in-all-circumstances-under-the-ihr-(2005).  

{7} World Organisation for Animal Health (WOAH). Avian influenza. Global situation. Available at: https://www.woah.org/en/disease/avian-influenza/#ui-id-2. 

{8} Food and Agriculture Organization of the United Nations. Global Avian Influenza Viruses with Zoonotic Potential situation update. Available at: https://www.fao.org/animal-health/situation-updates/global-aiv-withzoonotic-potential/bird-species-affected-by-h5nx-hpai/en. 

{9} World Organisation for Animal Health. Statement on High Pathogenicity Avian Influenza in Cattle, 6 December 2024. Available at: https://www.woah.org/en/high-pathogenicity-avian-influenza-hpai-in-cattle/. 

{10} World Health Organization. World Health Organization. International Health Regulations (2005), as amended through resolutions WHA67.13 (2014), WHA75.12 (2022), and WHA77.17 (2024). Available at: https://apps.who.int/gb/bd/pdf_files/IHR_2014-2022-2024-en.pdf. 

{11} World Health Organization. Case definitions for the four diseases requiring notification in all circumstances under the International Health Regulations (2005). Available at: https://www.who.int/publications/m/item/case-definitions-for-the-four-diseases-requiring-notification-towho-in-all-circumstances-under-the-ihr-(2005). 

{12} World Health Organization. Manual for the laboratory diagnosis and virological surveillance of influenza (2011). Available at: https://apps.who.int/iris/handle/10665/44518. 

{13} World Health Organization. Pandemic influenza preparedness framework for the sharing of influenza viruses and access to vaccines and other benefits, 2nd edition. Available at: https://iris.who.int/handle/10665/341850. 

{14} World Health Organization. Operational guidance on sharing influenza viruses with human pandemic potential (IVPP) under the Pandemic Influenza Preparedness (PIP) Framework (2017). Available at: https://apps.who.int/iris/handle/10665/259402. 

Source: 

Link: https://www.who.int/publications/m/item/influenza-at-the-human-animal-interface-summary-and-assessment--22-january-2026

____

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

 

A wild Greylag Goose in Lubelskie Region.

Source: 

Link: https://wahis.woah.org/#/in-review/7227

____

#Hungary - High pathogenicity avian #influenza #H5N1 viruses (Inf. with) (#poultry) - Immediate notification

 

Poultry farms in Békés Region.

Source: 

Link: https://wahis.woah.org/#/in-review/7228

____

#Genomic #features associated with sustained #mammalian #transmission of avian #influenza A viruses

 

Abstract

Comparably few lineages of influenza A virus (IAV) have evolved long-term sustained transmission in mammals. The reasons remain largely unknown, and the possibility of avian IAVs evolving sustained mammalian transmission is an ongoing concern. Here we measured the GC content and frequency of GC dinucleotides in 115,520 whole genomes of IAVs using bioinformatic analyses. We found that persistent mammalian lineages showed declining trends in GC-related content and could be reliably separated from IAVs circulating only in birds and those sporadically infecting mammals. Similarly, the earliest viruses of persistent mammalian lineages showed reduced GC-related content, suggesting that this trait might in part contribute to their eventual persistence. Recent highly pathogenic 2.3.4.4b H5 viruses that spread in mink, foxes and humans were also characterized by reduced GC-related content. While not sufficient, reduced GC-related content may be a necessary condition for sustained mammalian transmission and should be included in risk assessment tools for pandemic influenza.

Source: 

Link: https://www.nature.com/articles/s41564-025-02257-4

____

Genomic-based #biosurveillance for avian #influenza: whole genome sequencing from wild #mallards sampled during autumn migration in 2022–23 reveals a high co-infection rate on migration stopover site in #Georgia

 

Abstract

The Caucasus region, including Georgia, is an important intersection for migratory waterbirds, offering potential for avian influenza virus (AIV) transmission between populations from different geographic areas. In 2022 and 2023, wild ducks were sampled during autumn migration events in Georgia to study the genetic relationships and molecular characteristics of influenza strains. Sequencing and phylogenetic analysis were used to compare the sampled strains to reference sequences from Africa, Asia, and Europe, allowing assessment of genetic relationships and virus transmission between migratory birds. Protein language modeling identified potential co-infections. Of 225 duck samples, 128 tested positive for the influenza M gene. 55 influenza-positive samples underwent whole-genome sequencing, revealing significant diversity. Analysis of the hemagglutinin (HA) segment showed notable differences among subtypes. Most samples were H6N1 and H6N6, but co-infections with combinations like H6H3, N8N1, N6H9, N2N6, and H9H6/N1N2 were also identified. These findings demonstrate the high variability of influenza viruses in migratory waterbirds in Georgia, including a notable rate of co-infections. Some samples exhibited uncommon genetic characteristics compared to other strains from the same year, suggesting Georgia’s role as a mixing vessel for influenza viruses. This facilitates reassortment during co-infections and contributes to the genetic diversity observed across flyways.

Source: 

Link: https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1735728/full

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Detection of #LaCrosse Virus #RNA in Clinical #Specimens Obtained from #Children with La Crosse Infection

 

Highlights

• Viremia in children with La Crosse Virus infection is transient; viral RNA was detected in only 3.2% of sera

• Detection of La Crosse Virus RNA in respiratory samples is slightly higher at 21.7% and may reflect the temporal distribution of the virus after infection

• NAAT has limited utility in routine diagnosis of La Crosse Virus encephalitis in children but may still be useful in cases with delayed seroconversion

Abstract

Background

La Crosse virus (LACV), a member of family Peribunyaviridae, genus Orthobunyavirus, is the leading cause of neuroinvasive arboviral infection in children in the United States. Diagnosis relies on detecting specific antibodies (IgG or IgM), a 4-fold titer rise or seroconversion, in patients with compatible presentations. NAAT used for LACV detection has largely been limited to mosquito, animal models or postmortem brain tissue. There is a lack of data on the performance of NAATs in clinical specimens from living patients.

Methods

Children who had positive arbovirus serology tests and a diagnosis of LACV encephalitis were identified. Remnant specimens including plasma, serum, CSF, throat swab (THT) or nasopharyngeal sample (NP) submitted to the laboratory for other diagnostic testing were retrieved and tested with LACV-PCR. Medical records were reviewed for demographics, presenting symptoms and test results.

Results

From June 2015 to October 2021, 61 patients had remnant specimens available for LACV-PCR and were included in this study. A total of 179 clinical specimens from these patients were tested, including 64 sera, 31 plasma, 33 CSF, 23 THT and 28 NP. Ten (5.3%) samples collected from 8 (13.1%) unique patients were positive for LACV RNA. The positive rates were 3.2%, 0, 6.5%, 3.5% and 21.7% for sera, plasma, CSF, NP and THT respectively.

Conclusion

There is limited utility of NAATs for diagnosis of LACV infection. NAATs may be useful in cases with delayed seroconversion or in immunocompromised individuals.

Source: 

Link: https://www.sciencedirect.com/science/article/abs/pii/S1386653226000120?dgcid=rss_sd_all

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#Oseltamivir and #baloxavir monotherapy and combination #therapy efficacy against clade 2.3.4.4b #H5N1 #influenza virus infection in #ferrets

 

Abstract

Neuraminidase inhibitors (NAIs) and cap-dependent endonuclease inhibitors (CENIs) represent two classes of antiviral drugs recommended for early treatment of patients with seasonal influenza A virus (IAV) infections. However, only limited human data, particularly on combination antiviral treatment, are available to inform optimal dosing regimens against novel IAVs, including highly pathogenic avian influenza A(H5N1) virus, associated with severe disease. Clade 2.3.4.4b A(H5N1) viruses have caused outbreaks in avian and mammalian species worldwide, highlighting the need to assess antiviral drug efficacy against these strains. We challenged ferrets with a D1.1 genotype A(H5N1) virus and treated infected animals with the NAI oseltamivir phosphate (OST) and the CENI baloxavir acid (BXA), alone or in combination, with treatment onset commencing pre- or post-symptom onset (24- or 48-hours post-inoculation (p.i.), respectively). When administered pre- or post-illness onset, BXA, but not OST, monotherapy provided significant reduction of clinical signs and significantly decreased infectious viral levels (in both respiratory and extrapulmonary specimens) compared with mock-treated animals. Combination OST/BXA treatment, when administered pre- or post-symptom onset, resulted in significant improvements in both metrics versus OST monotherapy. These data support continued investigation of antiviral treatment modalities that include both NAI and CENI for patients with mild and severe A(H5N1) disease.

Source: 

Link: https://www.nature.com/articles/s42003-026-09607-w

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#Marburg virus disease - #Ethiopia [End of the Outbreak] (#WHO, Jan. 26 '26)

 

{Excerpt}

26 January 2026

Situation at a glance

On 26 January 2026, the Ministry of Health of Ethiopia declared the end of the Marburg virus disease (MVD) outbreak. 

This declaration came after two consecutive incubation periods (a total of 42 days) since the last person confirmed with MVD died and was given a safe and dignified burial, in accordance with WHO recommendations on 14 December 2025. 

As of 25 January 2026, a cumulative total of 19 cases, including 14 confirmed (including nine deaths) and five probable cases (all deaths), were reported. 

A total of 857 contacts listed for monitoring all had completed their 21-day follow-up as of 25 January 2026. 

WHO, through its country office and partners, provided technical, operational and financial support to the government to contain this outbreak.

Description of the situation

On 14 November 2025, after the laboratory confirmation of suspected viral hemorrhagic fever (VHF) cases in Jinka town, South Ethiopia Regional State, Ethiopia, the Ministry of Health of Ethiopia declared an outbreak of Marburg Virus Disease (MVD). 

Molecular testing conducted by the National Reference Laboratory at the Ethiopian Public Health Institute (EPHI) identified Marburg virus (MARV) in patient samples. 

This was the first time Ethiopia was reporting a MVD outbreak.

The first known case was an adult from Jinka town who developed symptoms on 23 October. 

The patient presented to the General Hospital the following day with vomiting, loss of appetite, and abdominal cramps. 

As of 25 January 2026, a cumulative total of 14 confirmed cases, including nine deaths (Case Fatality Rate (CFR) 64.3%) and five probable cases, all of whom had died, were reported by the Ministry of Health from Jinka, Malle and Dasench woredas in South Ethiopia Region and Hawassa in Sidama Region.

As of 25 January 2026, a total of 857 contacts were listed who completed 21 days of follow-up, 760 from the South Ethiopia Region and 97 from the Sidama Region. 

As of 5 January 2026, 3800 samples were tested for the virus.

On 26 January 2026, after two consecutive incubation periods (a total of 42 days), without a new confirmed case reported, after the last confirmed case died and was given a safe and dignified burial, on 14 December 2025, the Ministry of Health of Ethiopia declared the end of the MVD outbreak, as per WHO recommendations.

(...)

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON592

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

 

A wild Greylag Goose in Świętokrzyskie Region.

Source: 

Link: https://wahis.woah.org/#/in-review/7224

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