National #ONEHEALTH #Framework to Address #Zoonotic #Diseases and Advance Public Health #Preparedness in the #USA

Executive Summary 

The first ever National One Health Framework to Address Zoonotic Diseases and Advance Public Health Preparedness in the United States (NOHF-Zoonoses), 2025-2029, establishes a structure to facilitate multisectoral and transdisciplinary coordination, collaboration, and communication across the federal government. 

Using the One Health approach, the framework addresses zoonotic diseases and other priority One Health issues in the United States (U.S.). 

The One Health approach recognizes the interdependence of the health of humans, domestic and wild animals, plants, and the wider environment (including ecosystems). 

This approach mobilizes multiple diverse sectors, disciplines, and communities to work together to promote well-being and address health and ecosystem threats. 

Previous multisectoral work in the U.S. identified the critical need to formalize federal One Health coordination to address zoonotic diseases and other One Health related issues across the U.S. Government. 

Therefore, in the 2023 Consolidated Appropriations Act and the 2021 House Appropriations Committee Report, Congress directed the Centers for Disease Control and Prevention (CDC) in coordination with other federal agencies, to develop a framework based on the One Health approach to address zoonotic diseases and advance public health preparedness. 

The Act also directed CDC to coordinate with the U.S. Department of Agriculture (USDA) and the Department of the Interior (DOI) to develop a mechanism to support coordination at the federal level related to prevention, detection, control, and response for zoonotic diseases and related One Health activities. 

The One Health approach applies to zoonotic diseases as well as many other health threats at the interconnection between people, animals, plants, and the environment.  

While the primary focus of the NOHF-Zoonoses is addressing zoonotic diseases and advancing public health preparedness, the U.S. OHCU has also incorporated other components of One Health into this framework. 

To meet these directives CDC partnered with DOI, USDA and other federal agencies beginning in November 2021, to plan the establishment of the United States One Health Coordination Unit (U.S. OHCU) and to draft the NOHFZoonoses. 

The U.S. OHCU was launched in January 2024, with joint leadership from CDC (Chair 2024-2026), DOI, and USDA.  

The U.S. OHCU is coordinated by a Chair that will rotate between CDC, USDA, and DOI on a biennial calendar year basis. 

U.S. OHCU membership includes 24 agencies related to health, agriculture, interior, wildlife, environment, development, state, commerce, defense, security, and other fields. 

The draft NOHF-Zoonoses was published in September 2023 via the Federal Register Notice process, to engage and obtain input from state, Tribe, local, and territorial (STLT), non-governmental partners, and the public.  

The NOHF-Zoonoses presents goals and objectives for application of the One Health approach to protect people, animals, and our shared environment in the U.S. from zoonotic diseases and advance public health preparedness to optimize health, food safety and security, and sustainability while also promoting biodiversity and conservation outcomes. 

The NOHF-Zoonoses was designed to align with and complement existing U.S. initiatives that incorporate the One Health approach. 

The seven goals outlined in the NOHF-Zoonoses include the following areas: 

-- (1) Coordination, Collaboration and Communication; 

-- (2) Prevention; 

-- (3) Preparedness; 

-- (4) Coordinated Outbreak Investigation, Response, and Recovery; 

-- (5) Surveillance; 

-- (6) Laboratory; and 

-- (7) Workforce. 

While this framework focuses on One Health coordination at the federal level, its success depends on robust partnerships with STLT, non-governmental organizations, academia, and private sector partners as well as collaboration with relevant international partners. 

Knowledge and best practices from the implementation of the NOHF-Zoonoses will inform future One Health priorities and strengthen the nation’s ability to address One Health threats and promote health, safety, security, and resilience at the human-animal-plant-environment interface. 

Advancing One Health collaboration in the U.S. through the U.S. OHCU and the NOHF-Zoonoses will enhance our ability to jointly prevent, detect, and respond to zoonotic disease threats and related One Health issues. This initiative will improve efficiency across the U.S. government by enhancing collaboration across all relevant sectors with governmental and non-governmental partners while optimizing resource use in order to protect the health, safety, and security of people, animals, plants, and our shared environment.

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Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/one-health/media/pdfs/2025/01/354391-A-NOHF-ZOONOSES-508_FINAL.pdf

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Modulation of #cytokeratin and #cytokine/chemokine expression following #influenza virus infection of differentiated #human #tonsillar epithelial cells

ABSTRACT

The tonsils have been identified as a site of replication for Epstein–Barr virus, adenovirus, human papillomavirus, and other respiratory viruses. Human tonsil epithelial cells (HTECs) are a heterogeneous group of actively differentiating cells. Here, we investigated the cellular features and susceptibility of differentiated HTECs to specific influenza viruses, including expression of avian-type and mammalian-type sialic acid (SA) receptors, viral replication dynamics, and the associated cytokine secretion profiles. We found that differentiated HTECs possess more abundant α2,3-linked SA (preferentially bound by avian influenza viruses) than α2,6-linked SA (preferentially bound by mammalian strains). This dual receptor expression suggests a role in influenza virus adaptation and tropism within the tonsils by facilitating the binding and entry of multiple influenza virus strains. Our results indicated the susceptibility of differentiated HTECs to a wide range of influenza viruses from human, swine, and avian hosts. Virus production for most strains was detected as early as 1 day post-infection (dpi), and typically peaked by 3 dpi. However, pandemic H1N1 virus showed remarkably delayed replication kinetics that did not peak until at least 7 dpi. Notably, influenza virus infection impacted the expression of cytokeratins in HTEC cultures, which correlated with altered cytokine secretion patterns. These patterns varied within the strains but were most distinct in swine H3N2 infection. In conclusion, differentiated HTECs exhibited a strain-specific pattern of influenza virus replication and innate immune responses that included changes in cytokeratin and cytokine expression. These studies shed light on the complex interplay between influenza viruses and host cells in the tonsils.

Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.01460-24?af=R

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#Cambodia records 1st #human #death from #H5N1 in 2025

PHNOM PENH, Jan. 10 (Xinhua) -- A 28-year-old man from southeast Cambodia's Kampong Cham province died of H5N1 human avian influenza on Friday, becoming the first death in 2025, the Ministry of Health said in a press statement.

"Laboratory results from the National Institute of Public Health showed on Jan. 9, 2025 that the man was positive for H5N1 virus," the statement said.

"Although our team of doctors had provided him intensive care, the patient died on Jan. 10, 2025 due to his severe condition, with the symptoms of fever, cough, and dyspnea," it added.

The patient lived in village 22 in Chamkar Leu district's Chamkar Andoung commune.

"According to queries, the patient raised and fed chicken, and he cooked sick chicken for food," the statement said.

Health authorities are looking into the source of the infection and are examining any suspected cases or people who have been in contact with the victim in order to prevent an outbreak in the community, it added.

H5N1 influenza is a flu that normally spreads between sick poultry, but it can sometimes spread from poultry to humans, and its symptoms include fever, cough, runny nose, and severe respiratory illness.

The Ministry of Health called on people to be extra vigilant and not to eat ill or dead poultry, saying that bird flu still poses a threat to people's health.

From 2003 to date, there were 73 cases of human infection with H5N1 influenza, including 44 deaths in the Southeast Asian country, according to the ministry.

Source: Xinhua, https://english.news.cn/asiapacific/20250110/b1035982821244e2828ae53394c1129f/c.html

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

 A wild sanderling in Oostende.

Source: WOAH, https://wahis.woah.org/#/in-review/6175

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#Human #Health #Surveillance During Animal #Disease #Emergencies: #Minnesota Department of Health Response to Highly Pathogenic Avian #Influenza Outbreaks, 2015 and 2022–2023

ABSTRACT

Objectives

Highly pathogenic avian influenza (HPAI) poses an occupational risk for poultry workers, responders, and others in contact with infected birds. The objective of this analysis was to describe HPAI surveillance methods and outcomes, and highlight the challenges, successes, and lessons learned during the Minnesota Department of Health’s (MDH’s) public health response to HPAI outbreaks in Minnesota poultry flocks in the years 2015 and 2022–2023.

Methods

During both outbreaks, MDH staff attempted to contact all potentially exposed people and conduct a standardized interview. People were considered exposed and at risk if they had entered a barn with poultry on any HPAI test-positive premises. With their consent, exposed persons were entered into illness monitoring until 10 days from their last exposure. In 2015, MDH monitored the health of poultry workers only. In the 2022–2023 response, MDH monitored the health of poultry workers, backyard flock owners, responders, and private contract workers. In 2022–2023, interview responses were entered into a REDCap (Research Electronic Data Capture) database in real time, which automatically entered the person into monitoring if they consented. Through REDCap, they received an automated email with a unique link to a short survey asking about any symptom development. Where appropriate, interview responses from poultry workers collected in 2015 were compared to interview responses from poultry workers collected in 2022–2023.

Results

From March 3 to June 5, 2015, MDH epidemiologists interviewed and evaluated 375 (86%) of 435 poultry workers from 110 HPAI-infected flocks. From March 25, 2022 through December 31, 2023, MDH epidemiologists interviewed and evaluated 649 (65%) of 992 poultry workers, responders, contractors, and backyard flock owners associated with 151 HPAI-infected flocks. Among poultry workers, self-reported personal protective equipment (PPE) usage declined significantly from 2015 to 2022–2023 (full PPE usage 51.8% vs. 23.9%, p < .01).

Conclusion

MDH’s long standing relationships with animal health officials and the poultry industry resulted in strong poultry worker participation rates in surveillance efforts during HPAI outbreaks in 2015 and 2022–2023. Self-reported PPE usage was low, particularly in 2022–2023. Improvements in PPE accessibility and technology are needed to protect workers and responders in the on-going HPAI outbreak.

Source: Journal of Agromedicine, https://www.tandfonline.com/doi/full/10.1080/1059924X.2024.2442406

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Testing of #Retail #Cheese, #Butter, Ice Cream, and Other Dairy #Products for Highly Pathogenic Avian #Influenza in the #US

Abstract

The recent outbreak of highly pathogenic avian influenza (HPAI) in dairy cows has created public health concerns about the potential of consumers being exposed to live virus from commercial dairy products. Previous studies support that pasteurization effectively inactivates avian influenza in milk and an earlier retail milk survey showed viral RNA, but no live virus could be detected in the dairy products tested. Because of the variety of products and processing methods in which milk is used, additional product testing was conducted to determine if HPAI viral RNA could be detected in retail dairy samples, and for positive samples by quantitative real-time RT-PCR (qRT-PCR) further testing for the presence of live virus. Revised protocols were developed to extract RNA from solid dairy products including cheese and butter. The solid dairy product was mechanically liquified with garnet and zirconium beads in a bead beater diluted 1–4 with BHI media. This preprocessing step was suitable in allowing efficient RNA extraction with standard methods. Trial studies were conducted with different cheese types with spiked-in avian influenza virus to show that inoculation of the liquified cheese into embryonating chicken eggs was not toxic to the embryos and allowed virus replication. A total of 167 retail dairy samples, including a variety of cheeses, butter, ice cream, and fluid milk were collected as part of a nationwide survey. A total of 17.4% (29/167) of the samples had detectable viral RNA by qRT-PCR targeting the matrix gene, but all PCR-positive samples were negative for live virus after testing with embryonating egg inoculation. The viral RNA was also evaluated by sequencing part of the hemagglutinin gene using a revised protocol optimized to deal with the fragmented viral RNA. The sequence analysis showed all viral RNA-positive samples were highly similar to previously reported HPAI dairy cow isolates. Using the revised protocols, it was determined that HPAI viral RNA could be detected in a variety of dairy products, but existing pasteurization methods effectively inactivate the virus assuring consumer safety.

Source: Journal of Food Protection, https://www.sciencedirect.com/science/article/pii/S0362028X24002151?via%3Dihub

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Detection of #antibodies against #H5 subtype highly pathogenic avian #influenza viruses in multiple #raccoons in Tokachi District, #Hokkaido, #Japan, from 2022 to 2023

Abstract

In recent years, infection cases of H5 subtype highly pathogenic avian influenza viruses (HPAIVs) in wild mammals have increased globally. To obtain recent epidemiological information regarding influenza A virus (IAV) infection in raccoons (Procyon lotor), the prevalence of anti-IAV antibodies in sera was analyzed among raccoons captured in Tokachi District, Hokkaido, Japan, from 2019 to 2023. Screening of serum samples using enzyme-linked immunosorbent assay and agar gel precipitation test detected anti-IAV antibodies in 5 of 114 (4.4 %) raccoons. All positive sera were from raccoons captured from 2022 to 2023. The hemagglutination inhibition test revealed that all five serum samples contained anti-H5 subtype HPAIV antibodies, and one also contained anti-H1 subtype antibodies. The neuraminidase inhibition test revealed that all five sera contained anti-N1 subtype antibodies, and one also contained anti-N8 subtype antibodies. In the virus neutralization test, these five sera showed stronger neutralization activity against the H5 subtype clade 2.3.4.4b HPAIV strain recently circulating worldwide compared to the old H5 HPAIV strain isolated in Japan in 2007. These findings suggested that raccoons could be involved in the circulation of H5 HPAIVs in nature.

Source: Virus Research, https://www.sciencedirect.com/science/article/pii/S0168170224002089?via%3Dihub

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Susceptibility of #bovine respiratory and mammary epithelial #cells to avian and #mammalian derived clade 2.3.4.4b #H5N1 highly pathogenic avian #influenza viruses

Abstract

Zoonotic transmission of avian influenza viruses into mammals is relatively rare due to anatomical differences in the respiratory tract between species. Recently, clade 2.3.4.4b highly pathogenic H5N1 avian influenza viruses were detected circulating in North American cattle. Sporadic transmission between cattle, humans, and other animals proximal to cattle or after consuming products from infected cattle has occurred, but thus far there is no evidence of human-to-human transmission. However, the virus has the potential to adapt to the mammalian respiratory tract with every transmission event that occurs, making it crucial to understand cellular and species tropism of the H5N1 2.3.4.4b viruses. We compared viral kinetics of clade 2.3.4.4b viruses isolated from birds and mammals in respiratory epithelial cells derived from cattle, human, swine, and ferret. We found that avian derived viruses could replicate in swine cells only, yet mammalian derived strains could replicate efficiently in all tracheal and nasal epithelial cells tested. Interestingly, only bovine mammary epithelial cells (MEC) and swine respiratory epithelial cells were permissive to both avian and mammalian derived strains, possibly due to increased sialic acid expression on bovine MEC compared to bovine tracheal epithelial cells (TEC). However, sialic acid expression differed between dairy and beef cows: TEC derived from a dairy cow had increased expression of alpha2,6;2,3 sialic acid receptors compared to TEC from a beef-dairy cow cross. This study highlights the ability of clade 2.3.4.4b H5N1 viruses derived from mammals but not wild birds to infect the respiratory epithelium of other mammalian hosts.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.01.09.632235v1?rss=1

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Asymptomatic #infection and #antibody #prevalence to co-occurring avian #influenza viruses vary substantially between sympatric #seabird species following #H5N1 #outbreaks

Abstract

Emerging infectious diseases are of major concern to animal and human health. Recent emergence of high pathogenicity avian influenza virus (HPAIV) (H5N1 clade 2.3.4.4b) led to substantial global mortality across a range of host species. Co-occurring species showed marked differences in mortality, generating an urgent need for better epidemiological understanding within affected populations. We therefore tested for antibodies, indicative of previous exposure and recovery, and for active viral infection in apparently healthy individuals (n = 350) across five co-occurring seabird species on the Isle of May, Scotland, during 2023, following H5N1 HPAIV associated mortality in the preceding summer. Antibody prevalence to AIV subtypes varied substantially between species, ranging from 1.1% in European shags (Gulosus aristotelis) (to H5) to 78.7% in black-legged kittiwakes (Rissa tridactyla) (to H16 or both H13 and H16), and between 31 and 41% for three auk species (H5, H16 or both). At least 20.4% of auks had antibodies to an as yet unidentified subtype, suggesting further subtypes circulating in the population. We found low levels of active, but asymptomatic, AIV infection in individuals (1.6–4.5%), but excluded this as H5N1. Our results emphasise the importance of testing healthy individuals to understand the prevalence of co-circulating AIV subtypes in wild populations, and the potential for future reassortment events which could alter virus behaviour and impact.

Source: Scientific Reports, https://www.nature.com/articles/s41598-025-85152-6

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#Iceland, Avian #influenza #H5N5 in #cats

 {Original text in Icelandic, translated, edited.}

The Icelandic University of Iceland's Pathology Laboratory at Keldur notified the Icelandic Food and Veterinary Authority on January 6 that a kitten that arrived at the laboratory for autopsy had been diagnosed with a severe strain of avian influenza (H5N5). 

This is the same strain that has been detected in wild birds in Iceland since September last year and on one poultry farm in early December. 

The Icelandic Food and Veterinary Authority immediately issued instructions for disease control to prevent the spread of the infection and is now working to trace the infection. 

Symptoms of the disease in this cat included loss of appetite, weakness, stiffness, tremors, seizures and other neurological symptoms. 

Cat owners are asked to contact a veterinarian immediately if they notice such symptoms in their cats.

The cat diagnosed with bird flu was a 10-week-old kitten that died on December 22. The littermate the kitten was from and another kitten from the same litter died after a short illness two days earlier. They were not tested. 

The kitten's other littermates had left the home before the illness occurred and are all asymptomatic today. 

The cats are from Ísafjörður, but the kitten diagnosed with the infection had arrived in Reykjavík. The owners of all the cats have been contacted.

The Icelandic Food and Veterinary Authority believes that it is most likely that the cats were infected by an infected wild bird. 

At present, there is no evidence of infection in more cats, but the Icelandic Food and Veterinary Authority asks cat owners and veterinarians to be on the lookout for symptoms that may indicate avian influenza infection. 

There have been a number of diagnoses in wild birds in recent months, and therefore there is some risk that cats can become infected while hunting or from carcasses they come across. 

However, the Icelandic Food and Veterinary Authority does not believe the risk is so great that there is reason to warn against letting cats outside. 

People are, however, reminded to always maintain general hygiene when interacting with animals and caring for them. 

General information about avian influenza and guidelines for disease prevention can be found on the website of the Directorate of Health . 

It is worth noting that the risk of infection for people caused by the avian influenza virus is low, according to information on the website of the European Centre for Disease Prevention and Control (ECDC) .

In recent years, avian influenza has been increasingly detected in various species of mammals around the world. The most common type is the highly pathogenic H5N1 strain. This trend clearly demonstrates the virus's ability to adapt to new animal species. One of the greatest concerns worldwide is the current outbreak of avian influenza in dairy cows in the United States caused by the highly pathogenic H5N1 strain. However, the genotype of the virus in question has not yet been identified anywhere else in the world. Detailed information about this can be found on the websites of the United States Department of Agriculture USDA and the United States Centers for Disease Control and Prevention ( CDC) .

Few cases of the virulent H5N5 strain have been reported in mammals. This strain has been mainly found in wild birds in the Arctic, but last year it was also found in red foxes and lynx in Norway, otters in the Netherlands, lynxes in Finland, and red foxes, skunks, and raccoons in Canada. No cases of this strain in domestic animals have been reported to the World Organisation for Animal Health (WOAH) to date.

In recent years, WOAH has placed great emphasis on combating the spread of avian influenza and published on its website in December a call for all nations of the world to place greater emphasis on monitoring and actions to prevent the spread of dangerous avian influenza viruses.

The Icelandic Food and Veterinary Authority reiterates its recommendation to the public to report wild birds and wild mammals found dead, when the cause of death is not obvious. This is best done by registering a tip on the Icelandic Food and Veterinary Authority website. It is important to clearly describe the location, preferably by recording coordinates.

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Source: MAST, https://www.mast.is/is/um-mast/frettir/frettir/fuglainfluensa-i-ketti

Highly pathogenic avian #H5N1 #influenza A virus #replication in ex vivo #cultures of #bovine mammary #gland and teat tissues

{Excerpt}

Our data indicate that bovine H5N1 viruses can replicate efficiently in the epithelium of the bovine teat cistern, suggesting that they invade the mammary gland through the teat canal, which is more easily accessed by viruses. H5N1 virus is thought to be transmitted among lactating dairy cattle through contaminated milking equipment and/or milker's hands during milking[23]. Proper milking procedures are required to prevent spread of HPAI H5N1 viruses in dairy cattle, thereby minimizing the risk of transmission from cows to other mammals including humans.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2450029#d1e346

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#Philippines - High pathogenicity avian #influenza #H5N2 viruses (#poultry) (Inf. with) - Immediate notification

Backyard reared poultry in Camarines Norte Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6167

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#Iceland - #Influenza A #H5N5 viruses of high pathogenicity (Inf. with) ({household #cats}) (2017-) - Immediate notification [FINAL]

Three cats (one adult female and two 10 week old kittens) from the same household died on December 20., 21. and 22. after they had been ill for only a few days. The main clinical signs were lethargy, anorexia, cramps and stiffness. Other kittens from the same litter had been rehomed before those three got sick and they have not shown any symptoms. The most probable source of infection is wild birds. HPAI H5N5 have been diagnosed in a few wild birds in Iceland since September last year.

Source: WOAH, https://wahis.woah.org/#/in-review/6168

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#Greenland - #Influenza A #H5N5 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 A wild Northern Fulmar in Danish Exclusive Economic Zone (Greenland).

Source: WOAH, https://wahis.woah.org/#/in-review/6172

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#Evidence of avian and human #influenza A virus #infection in farmed Siamese #crocodiles (Crocodylus siamensis) in #Thailand

Abstract

Crocodilians are susceptible to a range of virus infection including influenza A virus (IAV). However, little is known about the ecology and epidemiology of IAV in crocodile species. This study aimed to investigate IAV infection in farmed Siamese crocodiles in central Thailand. We collected plasma samples and pharyngeal swab samples from Siamese crocodiles residing in 13 crocodile farms in 9 provinces of central Thailand during 2019. Additional archival plasma samples of Siamese crocodiles collected in 2012 and 2018 were also included in the study. Plasma samples were screened for influenza A antibodies by a hemagglutination inhibition (HI) assay and positive were evaluated by a cytopathic effect/hemagglutination based-microneutralization (MN) assay. Swab samples were tested for influenza viral RNA by a real-time RT-PCR assay targeting the influenza matrix (M) gene. Among 246 tested plasma samples, the overall seroprevalence of antibodies against IAV in farmed Siamese crocodiles was 17.5% (43/246). The most common hemagglutinin (HA) subtype was H2 (46.5%, 20/43) followed by H9 (39.5%, 17/43), human H1 (14%, 6/43) and H1 (7%, 3/43). Multiple HA subtypes were also detected in 7% (3/43) of infected crocodiles with combination of H1 and H2 subtypes. All 126 tested swab samples were negative for influenza viral RNA. In addition, we demonstrated the ability of wild-type IAV subtypes (H1, H2, H9 and human H1) to infect primary Siamese crocodile fibroblast cells. To our knowledge, this is the first report of serological evidences of avian and human IAV infection in Siamese crocodiles. Our findings highlighted the role of crocodile species in the ecology of IAV particularly the potential to serve as the reservoir or mixing vessel for the viruses that significantly threaten both human and animal health.

Source: PLoS One, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0317035

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Long-term immune responses induced by low-dose #infection with high pathogenicity avian #influenza viruses can protect #mallards from reinfection with a heterologous strain

Abstract

Migratory water birds are considered to be carriers of high pathogenicity avian influenza viruses (HPAIVs). In Japan, mallards are often observed during winter, and HPAIV-infected mallards often shed viruses asymptomatically. In this study, we focused on mallards as potential carriers of HPAIVs and investigated whether individual wild mallards are repeatedly infected with HPAIVs and act as HPAIV carriers multiple times within a season. Mallards were experimentally infected with H5N1 and H5N8 HPAIVs that were isolated recently in Japan and phylogenetically belong to different hemagglutinin groups (G2a, G2b, and G2d). All of these strains are more infectious to mallards than to chickens, and the infected mallards shed enough virus to infect others, regardless of whether they exhibited clinical signs. Serum antibodies to the homologous antigen, induced by a single infection with a low virus dose (10 times the 50% mallard infectious dose), were maintained at detectable levels for 84 days. Immunity at 84 days post-inoculation fully protected the mallards from a challenge with the homologous strain, as demonstrated by a lack of viral shedding, and antibody levels did not increase significantly in most of these birds. Protection against heterologous challenge was also observed despite undetectable levels of antibodies to the challenge strain. Our findings suggest that repeated infections with homologous and heterologous HPAIV strains do not occur frequently in individual wild mallards within a season, particularly at low viral doses, and the frequency with which they act as carriers may be limited.

Source: Archives of Virology, https://link.springer.com/article/10.1007/s00705-024-06209-x

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#Comparison of Contemporary and Historic Highly Pathogenic Avian #Influenza A(#H5N1) Virus #Replication in #Human #Lung #Organoids

Abstract

We compared virus replication and host responses in human alveolar epithelium infected with highly pathogenic avian influenza (HPAI) A(H5N1) viruses. A/Vietnam/1203/2004 replicated most efficiently, followed by A/Texas/37/2024, then A/bovine/Ohio/B24OSU-342/2024. Induction of interferon-stimulated genes was lower with A/Texas/37/2024 and A/bovine/Ohio/B24OSU-342/2024, which may indicate a reduced disease severity of those viruses.

Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/31/2/24-1147_article

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#Information for #Workers Exposed to #H5N1 #Birdflu {virus}

 {Summary}

At a glance

-- H5N1 bird flu is caused by viruses that can infect cows and other animals but most commonly affect birds and poultry. 

-- People who work with infected animals or their byproducts (for example, raw milk), might get sick from the virus. 

-- For example, dairy and poultry workers might get sick with H5N1 bird flu. 

-- Your employer should develop a workplace health and safety plan and share it with you. 

-- CDC updated this page to add information about worker exposure levels (low, medium, and high). 

-- We also added detail about how to use the right personal protective equipment safely for each exposure level.

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Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/bird-flu/prevention/farm-workers.html

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#Surveillance of Highly Pathogenic Avian #Influenza Virus in Wild #Canids from #Pennsylvania, #USA

Abstract

The avian influenza virus is a global pathogen with significant health and economic implications. While primarily a pathogen of wild and domestic birds, recent outbreaks of the H5N1 highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4b have caused mortality in a wide variety of mammals, including members of the Canidae family, on multiple continents. Despite sporadic mortality events globally, the epidemiology and pathobiology of H5N1 HPAIV in wild canids remains poorly defined. During 2022–2024, 41 wild canid carcasses (diagnostic cases), including 23 red foxes and 18 gray foxes, were tested for the influenza A virus (IAV) via PCR, with five red fox kits testing positive (12%). Infected animals had variably severe encephalitis, pneumonia, and occasionally myocarditis associated with strong immunolabeling for IAV. Serum from 269 wild canids in Pennsylvania was tested for antibodies to IAV, including 133 samples collected prior to 2021 (pre-H5N1 HPAIV 2.3.4.4b introduction) and 136 collected after 2022 (post-H5N1 HPAIV 2.3.4.4b introduction). All samples collected prior to 2021 were seronegative for IAV. Two coyotes from 2024 were seropositive for IAV but were negative for antibodies to the H5 and N1 subtypes. Collectively, these data suggest that while sporadic H5N1 HPAIV infection and mortality can occur in wild canids, particularly juvenile red foxes, infection was limited in these outwardly healthy and opportunistically sampled animals. Future studies should utilize a risk-based approach to target sampling of wild canids at increased risk for H5N1 HPAIV infection, such as those around waterfowl habitats or spatially around wild bird or domestic animal outbreaks.

Source: Animals, https://www.mdpi.com/2076-2615/14/24/3700

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#Analysis of the Monophyletic #Lineage of Avian #Influenza #H5N1 Which Circulated in #Venezuelan #Birds During the 2022–2023 #Outbreak

Abstract

Avian influenza subtype H5N1 has caused outbreaks worldwide since 1996, with the emergence of the Guandong lineage in China. The current clade 2.3.4.4b has evolved from this lineage, with increased virulence and mass mortality events in birds and mammals. The objective of this study was the analysis of 17 viral genomes of H5N1 avian influenza isolated in Venezuela during the 2022–2023 outbreak. The eight viral genomic segments were amplified using universal primers and sequenced via next-generation sequencing. The sequences were analyzed to confirm the H5 hemagglutinin clade, identify possible genetic reassortments, and perform a phylogenetic and docking analysis of the viral isolates. The viruses found in Venezuela belonged, as expected, to clade 2.3.4.4b and formed a monophyletic clade with North American influenza viruses, with no evidence of further reassortment. The introduction of the virus in South America is associated with bird migration through the Atlantic (Venezuela), Atlantic/Mississippi (Choco, Colombia), and Pacific migratory flyways, with the emergence of several viral lineages. Several mutations were found in all segments of the genome, although none of the key mutations was involved in mammalian adaptation. Moreover, in silico structural analysis suggests, as expected, that the viral hemagglutinin maintained a predilection for avian α2,3-linked sialic acid. The unprecedented pathogenic outbreak of avian influenza disease in South America was associated with the circulation of three different lineages, which maintain a lower affinity for the mammalian receptor.

Source: Microorganisms, https://www.mdpi.com/2076-2607/12/12/2519

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