Abstract
In autumn 2025, highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b virus, genotype EA-2024-DI.2.1, caused systemic infections leading to a mass mortality event among the western migrating subpopulation of Eurasian cranes (Grus grus) in Germany. Gregarious behavior at feeding and resting sites likely promoted rapid viral spread within the population.
Source:
Link: https://wwwnc.cdc.gov/eid/article/32/5/26-0170_article
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
New human cases {2}:
-- From 23 January to 31 March 2026, based on reporting date, detections of influenza A(H5N1) in four humans, influenza A(H9N2) in five humans, influenza A(H10N3) in one human, an influenza A(H1N1) variant ((H1N1)v) virus in one human, an influenza A(H1N2)v virus in one human, and influenza A(H3N2)v virus in one human were 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.
Risk management:
-- Candidate vaccine viruses (CVVs) for zoonotic influenza viruses for pandemic preparedness purposes were reviewed and updated at the February 2026 WHO consultation on influenza vaccine composition for use in the northern hemisphere 2026-2027 influenza season.
-- A detailed summary of zoonotic influenza viruses characterized since September 2025 is published here and updated CVVs lists are published here.
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 22 January 2026, four laboratory-confirmed human cases of A(H5N1) infection were detected in Bangladesh (one case) and Cambodia (three cases).
-- A(H5N1), Bangladesh
- On 9 February 2026, the National International Health Regulations Focal Point of Bangladesh notified WHO of a laboratory-confirmed human case of avian influenza A(H5) infection in a child from Chattogram Division.
- The patient, with no known comorbidities, developed symptoms on 21 January 2026 and was admitted to hospital on 28 January.
- A nasopharyngeal swab was collected on 29 January as part of the Hospital-based Influenza Surveillance (HBIS) platform for influenza-like illness (ILI) and severe acute respiratory infection (SARI) sentinel surveillance in Bangladesh.
- The patient was referred to a specialized private hospital and admitted to intensive care on 31 January.
- The patient died on 1 February.
- On 7 February, the Institute of Epidemiology, Disease Control and Research (IEDCR), serving as the National Influenza Centre (NIC), received and tested the sample, confirming influenza A(H5) by realtime reverse transcription polymerase chain reaction (RT-PCR) on the same day.
- Virus characterization and whole genome sequencing was conducted at International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), which confirmed that the A(H5N1) virus belongs to clade 2.3.2.1a of highly pathogenic avian influenza A(H5N1) virus (Gs/GD lineage), similar to the clade of viruses circulating in local poultry since around 2011.
- Genetic sequence data are available in GISAID (EPI_ISL_20367262; submission date 19 Feb 2026; Institute of Epidemiology, Disease Control & Research (IEDCR)).
- The case had exposure to household poultry, with two ducks and one chicken reportedly dying shortly before the case’s illness onset.
- Animal and environmental samples were collected and tested with RT-PCR and serology by the zoonotic investigation team of icddr,b.
- Two samples from ducks in the community and two samples from chicken meat in the freezer of household tested positive for influenza A(H5).
- Samples from symptomatic close human contacts tested negative for influenza.
- This is the first confirmed human case of avian influenza A(H5) reported in Bangladesh in 2026.
- In 2025, four human cases of avian influenza A(H5) 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(H5N1), Cambodia
- Between 15 February and 31 March 2026, Cambodia notified WHO of three laboratory-confirmed cases of A(H5N1) virus infection.
(...)
- All cases above had exposure to sick or dead backyard poultry.
- The first case was detected through SARI surveillance.
- The other two cases were detected following the detection of A(H5N1) in sick and dead poultry which initiated deployment of rapid response teams from the public health sector and active case finding.
- The last case was identified as having had exposure to sick and dead poultry, sampled and then developed ILI symptoms.
- Three human infections with A(H5N1) viruses have been confirmed in Cambodia in 2026 and none have been fatal.
- Influenza A(H5N1) viruses continue to be detected in domestic birds in Cambodia in 2026, including in areas where human cases have been detected.{9}
- Where the information is available, the genetic sequence data from the viruses from the human cases closely matches that from recent local animal viruses and are identified as clade 2.3.2.1e viruses.
- From the information available thus far on these recent human cases, there is no indication of human-to-human transmission of the A(H5N1) viruses.
-- A(H9N2), China
- Between 9 February and 20 March 2026, China notified WHO of four laboratory-confirmed cases of A(H9N2) virus infection.
(...)
-- A(H9N2), Italy, ex-Senegal {10}
- On 21 March 2026, Italy notified WHO of the detection of A(H9N2) virus in an adult male.
- The case had travelled to Senegal for more than six months and returned to Italy in mid-March 2026.
- Upon arrival in Italy, the case sought medical care, presenting with fever and persistent cough that had been present since mid-January.
- Laboratory investigations conducted on a bronchoalveolar lavage specimen on 16 March showed a positive Mycobacterium tuberculosis result, as well as detection of an un-subtypeable influenza A virus.
- The case was admitted to an isolation room under airborne precautions in a negative-pressure room and received antitubercular and antiviral treatment.
- As of 24 March, the patient was clinically stable and improving.
- On 20 March 2026, the regional reference laboratory confirmed the A(H9) subtype, and on 21 March, influenza A(H9N2) was confirmed by next-generation sequencing.
- Initial genetic findings suggest the infection was likely acquired from an avian source linked to Senegal.
- Additional samples have been sent to Italy’s National Influenza Center, where further characterization confirmed virus subtype Influenza A(H9N2), with close genetic similarity to strains previously identified in poultry in Senegal.
- No direct exposure to animals, wildlife or rural environments was identified.
- There was also no reported contact with symptomatic or confirmed human cases.
- Further epidemiological investigations on the source of exposure are ongoing.
- Contacts identified in Senegal were asymptomatic.
- All identified and traced contacts in Italy have tested negative for influenza and completed the period of active monitoring for the onset of symptoms and the quarantine required by national guidelines.
- Human infections with influenza A(H9) viruses have been reported from countries in Africa and Asia, where these viruses are also detected in poultry.
- This is the first imported human case of avian influenza A(H9N2) reported in the European Region.
-- 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, such as in the case reported by Italy.
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.
-- A(H10N3), China
- On 9 February 2026, China notified WHO of one laboratory-confirmed case of human infection with an avian influenza A(H10N3) virus in a 34-year-old man from Guangdong province who developed symptoms on 29 December 2025.
- On 1 January 2026, he was admitted to hospital and diagnosed with severe pneumonia, severe acute respiratory distress syndrome (ARDS) and sepsis.
- Oseltamivir treatment was initiated on 3 January.
- The patient's condition was stable at the time of reporting.
- On 12 January, the sample was sent to the provincial laboratory for testing.
- The result was positive for A(H10N3). On 14 January, the National Influenza Center confirmed the positive result.
- The patient works near two establishments that keep live poultry on the premises and chickens are present at the household.
- Environmental samples collected from sites related to likely poultry exposure, including the patient's home, the workplace and a nearby poultry market tested negative for A(H10N3) influenza virus.
- No further cases were detected among contacts of these cases.
- A total of 98 close contacts of the patient were traced.
- Since 2021, a total of seven cases of human avian influenza A(H10N3) virus infection have been reported globally and all were from China.
-- Risk Assessment for avian influenza A(H10N3):
- 1. What is the global public health risk of additional human cases of infection with avian influenza A(H10N3) viruses?
Human infections with avian influenza A(H10) viruses have been detected and reported previously.
The circulation and epidemiology of these viruses in birds have been previously reported.{12}
Avian influenza A(H10N3) viruses with different genetic characteristics have been detected previously in wild birds since the 1970s and more recently spilled over to poultry in some countries.
As long as the virus continues to circulate in birds, further human cases can be expected but remain unusual.
The impact to public health if additional sporadic cases are detected is minimal.
The overall global public health risk of additional sporadic human cases is low.
- 2. What is the likelihood of sustained human-to-human transmission of avian influenza A(H10N3) viruses?
No sustained human-to-human transmission has been identified associated with the event described above or past events with human cases of influenza A(H10N3) viruses.
Current epidemiologic and virologic evidence suggests that contemporary influenza A(H10N3) viruses assessed by the Global Influenza Surveillance and response System (GISRS) have not acquired 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(H10N3) 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 based on current limited evidence.
Swine influenza viruses in humans
-- Influenza A(H1N1)v, China
- On 20 March 2026, China notified WHO of a laboratory-confirmed case of A(H1N1)v influenza virus infection in a child from Yunnan province.
- The patient had onset of illness on 30 January 2026, was hospitalized on 2 February with pneumonia, and recovered in a few days.
- The patient had reported exposure to domestic pigs prior to illness onset.
-- Influenza A(H1N2)v, China
- On 3 February 2026, China notified WHO of a laboratory-confirmed case of A(H1N2)v influenza virus infection in a child from Yunnan province.
- The patient had onset of mild illness on 20 January 2026, and the infection was laboratory-confirmed on 2 February 2026.
- The patient had reported exposure to domestic pigs prior to illness onset. This case and the one above are not epidemiologically linked.
-- Influenza A(H3N2)v, Brazil
- On 26 January 2026, Brazil notified WHO of a laboratory-confirmed case of A(H3N2)v influenza virus infection.
- On 1 September 2025, a male child residing in the state of Mato Grosso do Sul presented with ILI symptoms and was taken to a health unit on 2 September.
- The patient had no reported comorbidities or recent travel history and reported being vaccinated against seasonal influenza in the last campaign.
- On 9 September, a respiratory sample was collected at the health unit, which is a sentinel unit for ILI.
- On 12 September, the Central Public Health Laboratory of Mato Grosso do Sul (Lacen/MS) reported that the RT-qPCR test for influenza A virus subtyping amplified the influenza A marker along with the H3 marker, indicating a swine-origin variant of the influenza H3 virus.
- The sample was sent to the National Influenza Center (NIC) of the Adolfo Lutz Institute, where the A(H3N2)v was confirmed by molecular tests and genomic sequencing.
- The sequences were entered into GISAID on 1 October.
- The sample was also shared with the WHO Collaborating Centre at the US Centers for Disease Control and Prevention (CDC), where it was genomically and antigenically characterized.
- An epidemiological investigation was conducted, which identified the case as a student at an agricultural school where pigs and laying hens are raised, although the institution's coordinators reported that the students had not had direct contact with pigs recently.
- It was reported that the case had contact with classmates who presented ILI symptoms during this period.
- All household contacts were vaccinated against seasonal influenza in the 2025 season, except for the patient's mother.
- To date, no other human cases of infection with the A(H3N2)v virus have been detected in association with this case.
-- Risk Assessment:
- 1. What is the public health risk of additional human cases of infection with swine influenza viruses?
Swine influenza viruses circulate in swine populations in many regions of the world.
Depending on geographic location, the genetic characteristics of these viruses differ.
Most human cases are exposed to swine influenza viruses through contact with infected animals or contaminated environments.
Human infection tends to result in mild clinical illness in most cases.
Since these viruses continue to be detected in swine populations, further human cases are expected.
The impact to public health if additional sporadic cases are detected is minimal.
The overall risk of additional sporadic human cases is low.
- 2. What is the likelihood of sustained human-to-human transmission of swine influenza viruses?
No sustained human-to-human transmission was identified associated with the events described above.
Current evidence suggests that contemporary swine influenza viruses have not acquired 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 swine influenza viruses by travelers?
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 that these viruses have not acquired the ability to transmit easily among humans.
For more information on zoonotic influenza viruses, see the report from the WHO Consultation on the Composition of Influenza Virus Vaccines for Use in the 2026-2027 Northern Hemisphere Influenza Season that was held on 23-26 February 2026 at this link.
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.{11}
- 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).{12,13}
- State Parties to the IHR (2005) are required to immediately notify WHO of any laboratory-confirmed{14} case of a recent human infection caused by an influenza A virus with the potential to cause a pandemic{15}.
- 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 basis16 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. WAHIS. https://wahis.woah.org/#/in-review/7409.
{10} World Health Organization. World Health Organization (10 April 2026). Disease Outbreak News: Avian Influenza A(H9N2) in Italy (https://www/who.int/emergencies/disease-outbreak-news/item/2026-DON597).
{11} World Organisation for Animal Health. Statement on High Pathogenicity Avian Influenza in Cattle, 6 December 2024 (https://www.woah.org/en/high-pathogenicity-avian-influenza-hpai-in-cattle/).
{12} World Health Organization. International Health Regulations (2005), as amended through resolutions WHA67.13 (2014), WHA75.12 (2022), and WHA77.17 (2024) (https://apps.who.int/gb/bd/pdf_files/IHR_20142022-2024-en.pdf).
{13} World Health Organization. Case definitions for the four diseases requiring notification in all circumstances under the International Health Regulations (2005) (https://www.who.int/publications/m/item/casedefinitions-for-the-four-diseases-requiring-notification-to-who-in-all-circumstances-under-the-ihr-(2005)).
{14} World Health Organization. Manual for the laboratory diagnosis and virological surveillance of influenza (2011) (https://apps.who.int/iris/handle/10665/44518).
{15} World Health Organization. Pandemic influenza preparedness framework for the sharing of influenza viruses and access to vaccines and other benefits, 2nd edition (https://iris.who.int/handle/10665/341850).
{16} World Health Organization. Operational guidance on sharing influenza viruses with human pandemic potential (IVPP) under the Pandemic Influenza Preparedness (PIP) Framework (2017) (https://apps.who.int/iris/handle/10665/259402).
Source:
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Abstract
The 2022 highly pathogenic avian influenza (HPAI) outbreak of H5N1 clade 2.3.4.4b was one of the major avian influenza outbreaks, leading to multiple spillover events infecting domestic and wild bird flocks, as well as mammals. The sustained spread was a result of viral circulation in wild birds across migratory flyways in North America. Pennsylvania has a significant poultry population that supports both retail and live bird markets. The state also features migratory bird stopovers on the Atlantic flyway, increasing exposure to HPAI infections. This study investigates clinical presentation and sequence data from H5N1 clade 2.3.4.4b viruses during the 2022 outbreak in Pennsylvania. Eight different H5N1 clade 2.3.4.4b genotypes were detected (A1, B1.1, B1.2, B1.3, B2.2, B3.3, B3.5, and one minor genotype) during the first year. The earliest detection was genotype A1, a fully Eurasian virus, in commercial poultry in April 2022. All other genotypes identified were reassortants of A1 with North American avian influenza gene segments (denoted with “B”). Genotype B3.3 was a rare genotype prior to the initial spillover into the live bird market system, but remained predominant among backyard flocks in Pennsylvania and surrounding states until September 2023. Genotype B3.3 has not been detected in migratory waterfowl since, suggesting the genotype has waned and is no longer in circulation. This study sheds light on the genotype diversity of H5N1 during the 2022 outbreak in Pennsylvania poultry, contributing to the understanding of virus evolution and its potential impacts.
Source:
Link: https://www.mdpi.com/1999-4915/18/5/502
____
I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Abstract
Background and Aim:
Middle East respiratory syndrome coronavirus (MERS-CoV) remains a persistent zoonotic threat more than a decade after its first detection, with Saudi Arabia continuing to be the global epicenter of human infections and the main reservoir interface through dromedary camels. Despite ongoing surveillance, advances in molecular diagnostics, and research on vaccines and therapeutics, sporadic zoonotic spillovers and healthcare-associated outbreaks still occur, showing that current prevention strategies are still not enough. This review compiles current evidence from epidemiological studies, camel reservoir research, genomic monitoring, and public health reports published between 2012 and April 2025 to identify the key gaps preventing effective containment. Special focus is given to recent genomic discoveries, including post-2022 clade B sublineages, recombination events, and spike protein changes that might affect transmission and the effectiveness of countermeasures. Available data suggest that MERS-CoV epidemiology is driven by repeated camel-to-human transmission, followed by occasional amplification in healthcare settings rather than sustained community spread. High seroprevalence and frequent detection of viral RNA in juvenile camels, seasonal gathering in markets, and extensive animal movement networks contribute to ongoing viral circulation at the animal–human interface. Genomic studies consistently show close phylogenetic relationships between camel and human isolates, confirming recurrent zoonotic transmissions. However, fragmented surveillance systems, delayed genomic data integration, inconsistent biosecurity practices, and limited field evidence for camel vaccination pose major barriers to control. Additionally, hospital outbreaks continue to occur due to delayed diagnosis, overcrowding, and incomplete adherence to infection-prevention protocols, underscoring the need for improved clinical preparedness. Based on the integrated synthesis of epidemiological, veterinary, and genomic evidence, this review proposes an implementation-focused One Health genomic framework tailored to the Saudi context. The proposed roadmap highlights real-time connection of human and camel surveillance, expands genomic sequencing capacity, targets vaccination strategies in camels and high-risk human populations, standardizes biosecurity measures in markets and abattoirs, and strengthens infection control systems in healthcare facilities. Alignment with national governance structures and Saudi Vision 2030 offers a practical pathway for coordinated multi-sectoral action. This review concludes that MERS-CoV is unlikely to be eradicated soon, but it can be effectively managed through a genomics-enabled, operational One Health approach that combines surveillance, vaccination, clinical preparedness, and policy coordination. The model outlined here provides a scalable way to reduce zoonotic spillover risk and strengthen readiness against future coronavirus and emerging zoonotic threats.
Source:
Link: https://veterinaryworld.org/Vol.19/March-2026/29.php
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
{Excerpts}
(...)
{-- H5N1:}
- Date of report: 22/04/2026
- Country: Cambodia
- Province / Region: Svay Rieng province
- District / City: Romduol district
- Sex: Female
- Age: 66
- Condition at time of reporting: Hospitalised
- Subtype of virus: H5N1
(...)
Source:
Link: https://www.chp.gov.hk/files/pdf/2026_avian_influenza_report_vol22_wk17.pdf
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Abstract
We tested wild ruminants, boar, and carnivores in northeast Germany for highly pathogenic avian influenza subtype H5 antibodies. Wild ruminants were seronegative, but 3.5% of boar and 12.5%–21.9% of carnivores were seropositive, indicating frequent spillover. Because such events might accelerate mammalian (and ultimately human) adaptation, sustained monitoring remains essential.
Source:
Link: https://wwwnc.cdc.gov/eid/article/32/5/25-1555_article
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Abstract
Background:
Highly pathogenic avian influenza H5N1 viruses of clade 2.3.4.4b have spread globally since 2021, causing extensive outbreaks in avian populations and repeated spillovers into diverse mammalian hosts, including humans. These cross-species transmission events highlight ongoing pandemic risks and underscore the need for vaccine strategies that reflect viral evolution at the human–animal interface. Despite the availability of licensed H5 vaccines and newly recommended World Health Organization (WHO) candidate vaccine viruses (CVVs), the extent to which these vaccines elicit cross-reactive antibody responses against contemporary clade 2.3.4.4b viruses, including mammalian spillover isolates of avian origin, remains incompletely characterized.
Method:
In this study, ferret antisera were generated using four WHO-recommended H5 CVVs, including a clade 1 strain (A/Vietnam/1194/2004) and three clade 2.3.4.4b strains (A/Astrakhan/3212/2020, A/American wigeon/South Carolina/22-000345-001/2021, and A/Ezo red fox/Hokkaido/1/2022), formulated with alum adjuvant to reflect licensed vaccine formulation used in national preparedness programs. Antibody responses and cross-reactive activity were evaluated using hemagglutination inhibition (HI) and microneutralization (MN) assays against homologous vaccine strains and a feline-origin clade 2.3.4.4b H5N1 field isolate from Korea, A/Feline/Korea/SNU-01/2023.
Results:
Antisera induced by clade 2.3.4.4b CVVs showed cross-reactive antibody responses against homologous and heterologous clade 2.3.4.4b viruses and demonstrated measurable HI and MN responses against the feline-origin field isolate. In contrast, antisera raised against the clade 1 Vietnam CVV exhibited limited cross-reactivity against clade 2.3.4.4b viruses. Overall, clade 2.3.4.4b CVVs generally showed higher antibody responses than the clade 1 vaccine strain across multiple panels.
Conclusions:
These findings provide descriptive insights into antigenic differences between clade 1 and clade 2.3.4.4b viruses and support the antigenic relevance of clade 2.3.4.4b CVVs for contemporary H5N1 strains. This study highlights the importance of ongoing antigenic evaluation to inform vaccine strain selection within a One Health framework.
Source:
Link: https://www.mdpi.com/2076-393X/14/4/301
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Abstract
Seasonal trends in infectious diseases are shaped by climatic and social factors, with many respiratory viruses peaking in winter. However, the seasonality of COVID-19 remains in dispute, with significant waves of cases across the United States occurring in both winter and summer. Using wavelet analysis of COVID-19 cases during the pandemic period, we find that the periodicity of epidemic COVID-19 varies markedly across the U.S. and correlates with winter temperatures, indicating seasonal forcing. However, seasonal forcing alone cannot explain the pattern of multiple waves per year that has been so characteristic of COVID-19. Using a modified SIRS model that allows specification of the tempo of waning immunity, we show that specific forms of non-durable immunity can sufficiently explain the sub-annual waves characteristic of the COVID-19 epidemic.
Source:
Link: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014169
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Abstract
We conducted a retrospective phylogenetic analysis of Mayaro virus (MAYV) detected in French Guiana during 1996–2024. Analysis revealed circulation of MAYV genotype D sublineage 2 and suggested introduction from Brazil and spread to Haiti and Venezuela. Phylogenetic findings support endemic circulation and reinforce the need for MAYV surveillance in the region.
Source:
Link: https://wwwnc.cdc.gov/eid/article/32/5/25-1435_article
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Di Patafisik - Opera propria, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=175713586
Source:
Link: https://it.wikipedia.org/wiki/Ferrovia_Cogne-Acque_Fredde
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
{Click on image to enlarge}
Public Domain.
Source:
Link: https://www.wikiart.org/en/hendrick-terbrugghen/st-sebastian-tended-by-irene-and-her-maid-1625
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Abstract
Background
Influenza A viruses pose a persistent pandemic threat. We report safety, reactogenicity, and immunogenicity findings for mRNA-1018 pandemic influenza vaccine candidates from a phase 1/2 study in healthy adults.
Methods
In Part A, participants were randomized to receive 1 of 4 mRNA-1018 candidates at 1 of 3 dose levels across 2 influenza A groups: (1) H5N8/H5-only or (2) H7N9/H7-only. H5N8 and H7N9 candidates were administered at 25, 50, or 100-µg and H5-only and H7-only at 12.5, 25, or 50-µg. Part B participants were randomized to receive 12.5, 25, or 50-µg H5-only-CG. Primary objectives were to evaluate the safety and reactogenicity of vaccine candidates. Secondary objectives included evaluation of humoral immunogenicity through day 205 by hemagglutination inhibition (HAI), neuraminidase inhibition, and microneutralization assays.
Results
Parts A and B comprised 1195 and 304 dosed participants, respectively. Overall, solicited local adverse reactions (ARs) within 7 days of vaccination occurred in 76.8% of participants across vaccine candidates and dose levels, most commonly injection-site pain. Solicited systemic ARs were reported in 62.8% of participants, most frequently fatigue and headache. Solicited ARs were predominantly grade 1–2 in severity, with few grade 3 and no grade 4 events. Post-vaccination immune responses, assessed absolutely, by HAI titers and dynamically, by seroconversion rates, tended to increase with vaccine dose. H5-based candidates induced stronger strain-specific HAI, but with comparable microneutralization titers, versus H7-based candidates.
Conclusions
Vaccine candidates were sufficiently well-tolerated and immunogenic. Further development of mRNA pandemic influenza vaccines is warranted for pandemic preparedness.
Source:
Link: https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciag278/8662346
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I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Ann Intern Med
I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
Ann Intern Med
I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.
