#USA, Novel Influenza A #H5N1 Virus, four new cases detected in week 50/2024 {2 in #California, 1 in #Louisiana, 1 in #Delaware} (US #CDC FluView)

{Excerpt}

Three confirmed cases and one probable influenza A(H5) case were reported to CDC this week. 

To date, human-to-human transmission of influenza A(H5) virus has not been identified in the United States.

Two of these confirmed cases were reported by the California Department of Public Health. The cases occurred in a workers aged ≥18 years at a commercial dairy cattle farm in an area where highly pathogenic avian influenza (HPAI) A(H5N1) viruses had been detected in cows. The individuals had mild symptoms, which they reported to local health department officials. There have now been 34 total confirmed cases and one probable case in California.

The other confirmed case was reported by the Louisiana Department of Health. This case occurred in an individual aged ≥18 years. This individual developed respiratory symptoms during week 48 and was hospitalized with their illness. A respiratory specimen was collected at the healthcare facility and tested positive for influenza A, but negative for seasonal virus subtypes. The specimen was sent to the Louisiana Public Health Laboratory for further testing, where it tested presumptive positive for influenza A(H5) virus using the CDC influenza A(H5) assay. Influenza A(H5) virus was confirmed at CDC. The investigation by public health officials identified exposure to backyard poultry prior to the patient's illness onset. The patient remains hospitalized. This is the first influenza A(H5) case in Louisiana and the first instance of severe illness from influenza A(H5) virus infection in the United States.

The probable case was reported by the Delaware Division of Public Health. The case occurred in an individual aged ≥18 years. This individual developed respiratory symptoms during week 48 and sought healthcare for their illness. A respiratory specimen was collected at the healthcare facility and tested positive for influenza A. The specimen was sent to the Delaware Public Health Laboratory for routine surveillance, where it tested presumptive positive for influenza A(H5) virus using the CDC influenza A(H5) assay. The specimen was negative for influenza A(H5) virus using diagnostic RT-PCR at CDC. The investigation by public health officials did not find any exposure to poultry or cows or consumption of raw dairy products prior to the patient's illness onset. The patient has since recovered. This is the first probable case in Delaware.

Notification of the case reported by the Louisiana Department of Health to WHO was initiated per International Health Regulations (IHR). More information regarding IHR can be found at http://www.who.int/topics/international_health_regulations/en/. 

No additional notification to WHO of the probable case or confirmed cases exposed to dairy cows in California is required per International Health Regulations (IHR).

The CSTE position statement, which includes updated case definitions for confirmed, probable, and suspected cases is available at http://www.cste.org/resource/resmgr/position_statements_files_2023/24-ID-09_Novel_Influenza_A.pdf

An up-to-date human case summary during the 2024 outbreak by state and exposure source is available at www.cdc.gov/bird-flu/situation-summary/index.html

Information about avian influenza is available at https://www.cdc.gov/flu/avianflu/index.htm.

Interim recommendations for Prevention, Monitoring, and Public Health Investigations are available at https://www.cdc.gov/bird-flu/prevention/hpai-interim-recommendations.html.

The latest case reports on avian influenza outbreaks in wild birds, commercial poultry, backyard or hobbyist flocks, and mammals in the United States are available from the USDA at https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/2022-hpai.

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Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/fluview/surveillance/2024-week-50.html

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

 A wild Eurasian Lynx in Troms Og Finnmark.

Source: WOAH, https://wahis.woah.org/#/in-review/6117

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

 Forty Southern elephant seal (WILD), Sealion Island.

Source: WOAH, https://wahis.woah.org/#/in-review/6118

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

 A wild red fox in Podravska Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6119

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#Influenza Virus #Surveillance from the 1918 Influenza #Pandemic to the 2020 #Coronavirus Pandemic in #NewYork State, #USA

Abstract

A historical perspective of more than one hundred years of influenza surveillance in New York State demonstrates the progression from anecdotes and case counts to next-generation sequencing and electronic database management, greatly improving pandemic preparedness and response. Here, we determined if influenza virologic surveillance at the New York State public health laboratory (NYS PHL) tests sufficient specimen numbers within preferred confidence limits to assess situational awareness and detect novel viruses that pose a pandemic risk. To this end, we analyzed retrospective electronic data on laboratory test results for the influenza seasons 1997–1998 to 2021–2022 according to sample sizes recommended in the Influenza Virologic Surveillance Right Size Roadmap issued by the Association of Public Health Laboratories and Centers for Disease Control and Prevention. Although data solely from specimens submitted to the NYS PHL were insufficient to meet surveillance goals, when supplemented with testing data from clinical laboratories participating in surveillance programs, the recommended surveillance goals were achieved. Despite the sudden decline in influenza cases in 2020–2021, impacted by the COVID-19 mitigation measures, the dramatic increases in influenza cases surrounding the coronavirus pandemic reveal that influenza remains a national and international public health threat. Sample submissions to public health laboratories must be encouraged to facilitate monitoring for emerging viruses and preparedness for another pandemic.

Source: Viruses, https://www.mdpi.com/1999-4915/16/12/1952

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#Persistence of #Oropouche virus in #body #fluids among imported cases in #France, 2024

{Extract}

Since late 2023, more than 10 000 locally acquired cases of Oropouche virus have been reported in the Americas.1 Here, we describe the first cluster of Oropouche virus imported into France from Cuba, where transmission has been ongoing since at least May, 2024.2 Oropouche virus infection was documented in a group of five women (patients 1–5, confirmed cases) travelling to Cuba with two infants (patients 6–7, suspect cases) between July 28 and Aug 14, 2024. During their stay, patients 1–5 developed a dengue-like syndrome lasting 2–11 days, presenting symptoms similar to those described in the literature for Oropouche virus infection (appendix p 8).3 After recovery, patients 1, 2, and 5 experienced symptom relapse upon their return to France; the observed relapse rate aligns with recent estimates suggesting that 60% of patients with Oropouche virus experience a biphasic illness (appendix pp 7–8).4 During relapse, patient 1 sought medical advice, becoming the first diagnosed Oropouche virus case in this series and leading to the investigation of the cluster.

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Source: Lancet Infectious Diseases, https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(24)00815-6/fulltext?rss=yes

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Use of #equine #H3N8 #hemagglutinin as a broadly protective #influenza #vaccine immunogen

Abstract

Development of an efficacious universal influenza vaccines remains a long-sought goal. Current vaccines have shortfalls such as mid/low efficacy and needing yearly strain revisions to account for viral drift/shift. Horses undergo bi-annual vaccines for the H3N8 equine influenza virus, and surveillance of sera from vaccinees demonstrated very broad reactivity and neutralization to many influenza strains. Subsequently, vaccinating mice using the equine A/Kentucky/1/1991 strain or recombinant hemagglutinin (HA) induced similar broadly reactive and neutralizing antibodies to seasonal and high pathogenicity avian influenza strains. Challenge of vaccinated mice protected from lethal virus challenges across H1N1 and H3N2 strains. This protection correlated with neutralizing antibodies to the HA head, esterase, and stem regions. Vaccinated ferrets were also protected after challenge with H1N1 influenza A/07/2009 virus using whole viral or HA. These data suggest that equine H3N8 induces broad protection against multiple influenzas using a unique antigen that diverges from other universal vaccine approaches.

Source: npj Vaccines, https://www.nature.com/articles/s41541-024-01037-1

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Respiratory Virus-Specific and #Time-Dependent #Interference of #Adenovirus Type 2, #SARS-CoV-2 and #Influenza Virus #H1N1pdm09 During Viral Dual Co-Infection and Superinfection In Vitro

Abstract

Background. 

Understanding the interference patterns of respiratory viruses could be important for shedding light on potential strategies to combat these human infectious agents. 

Objective. 

To investigate the possible interactions between adenovirus type 2 (AdV2), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A/H1N1 pandemic (H1N1pdm09) using the A549 cell line. 

Methods. 

Single infections, co-infections, and superinfections (at 3 and 24 h after the first virus infection) were performed by varying the multiplicity of infection (MOI). Virus replication kinetics and the mRNA expression of IFN-α, IL-1α and IL-6 were assessed by real-time qPCR. 

Results. 

Co-infection experiments showed different growth dynamics, depending on the presence of the specific virus and time. AdV2 replication remained stable or possibly enhanced in the presence of co-infection with each of the two H1N1pdm09 and SARS-CoV-2 viruses used. In contrast, SARS-CoV-2 replication was facilitated by H1N1pdm09 but hindered by AdV2, indicating possible different interactions. Finally, H1N1pdm09 replication exhibited variably effectiveness in the presence of AdV2 and SARS-CoV-2. Superinfection experiments showed that the replication of all viruses was affected by time and MOI. The mRNA expression of IFN-α, IL-1α and IL-6 showed divergent results depending on the virus used and the time of infection. 

Conclusions. 

Further investigation of co-infection or superinfection may be helpful in understanding the potential relationship involved in the outcome of viral respiratory infection in the human population.

Source: Viruses, https://www.mdpi.com/1999-4915/16/12/1947

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Are we cultivating the perfect #storm for a #human avian #influenza #pandemic?

Abstract

The emergence of highly pathogenic avian influenza (HPAI) A H5N1 virus in dairy cattle marks a troubling new chapter in the ongoing battle against zoonotic diseases. Since its initial detection in 1955, the H5N1 virus has primarily been associated with poultry, posing significant threats to both animal and human health. However, recent outbreaks in U.S. dairy herds across nine states have revealed an alarming expansion of the virus, with over 190 herds affected as of September 2024. This unprecedented spread in cattle has sparked intense concern among scientists and health officials, especially with reports indicating that up to 20% of dairy products may contain traces of the virus. The implications of the H5N1 virus establishing itself in cattle populations are profound. This potential endemic presence could transform dairy farms into reservoirs of the virus, facilitating its evolution and increasing the risk of human transmission. Mutations enhancing viral replication in mammals have already been identified, including the notorious PB2 E627K mutation linked to increased virulence. Moreover, the detection of the virus in the central nervous system of infected animals, including cats, underscores the broad tissue tropism and severe pathogenic potential of the H5N1 virus. Current containment efforts include stringent biosecurity measures and financial incentives for enhanced testing and personal protective equipment (PPE) for farmers. Yet, gaps in testing infrastructure and the resurgence of raw milk consumption pose significant challenges. The U.S. Department of Agriculture (USDA) and the Centers for Disease Control and Prevention (CDC) emphasize the critical need for comprehensive testing and pasteurization to mitigate the risk of human infection. As the scientific community races to adapt existing antiviral treatments and develop effective vaccines, the concept of a One Health approach becomes increasingly vital. This holistic strategy calls for coordinated actions across human, animal, and environmental health sectors to preemptively tackle emerging zoonotic threats. Strengthening surveillance, fostering international cooperation, and investing in research are essential steps to prevent the H5N1 virus from igniting the next global health crisis. The current avian influenza outbreak serves as a stark reminder of the delicate balance between human activities and viral evolution. Our collective ability to respond effectively and proactively will determine whether we can avert the perfect storm brewing on the horizon.

Source: Biological Research, https://biolres.biomedcentral.com/articles/10.1186/s40659-024-00570-6

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Revealing novel #CD8+ T-cell #epitopes from the #H5N1 avian #influenza virus in HBW/B1 haplotype #ducks

Abstract

The duck CD8+ T-cell response effectively defends against H5N1 highly pathogenic avian influenza virus (HPAIV) infection, but the recognized peptide is rarely identified. Here, we found that the ratio of CD8+ T cells and the expression of IFN-γ and cytotoxicity-associated genes, including granzyme A/K, perforin and IL2, at 7 days post-infection in peripheral blood mononuclear cells (PBMCs) from B1 haplotype ducks significantly increased in the context of defending against H5N1 AIV infection in vivo. Moreover, similar results were observed in cultured and sorted H5N1 AIV-stimulated duck CD8+ T cells in vitro. Next, we selected 109 epitopes as candidate epitopes on the basis of the MHC-I restriction binding peptide prediction website database and further identified twelve CD8+ T-cell epitopes that significantly increased IFN-γ gene expression after stimulating B1 haplotype duck memory PBMCs. In particular, NP338−346, NP473−481, M2−10, PB1540−548 and PA80−88 were highly conserved in H5N1, H5N6, H5N8, H7N9, and H9N2 AIVs. These findings provide directions for the development of universal T-cell epitope vaccines for AIV in ducks.

Source: Veterinary Research, https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-024-01415-6

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An #influenza #mRNA #vaccine protects #ferrets from lethal #infection with highly pathogenic avian #influenza A(#H5N1) virus

Abstract

The global spread of the highly pathogenic avian influenza (HPAI) A(H5N1) virus poses a serious pandemic threat, necessitating the swift development of effective vaccines. The success of messenger RNA (mRNA) vaccine technology in the COVID-19 pandemic, marked by its rapid development and scalability, demonstrates its potential for addressing other infectious threats, such as HPAI A(H5N1). We therefore evaluated mRNA vaccine candidates targeting panzootic influenza A(H5) clade 2.3.4.4b viruses, which have been shown to infect a range of mammalian species, including most recently being detected in dairy cattle. Ferrets were immunized with mRNA vaccines encoding either hemagglutinin alone or hemagglutinin and neuraminidase, derived from a 2.3.4.4b prototype vaccine virus recommended by the World Health Organization. Kinetics of the immune responses, as well as protection against a lethal challenge dose of A(H5N1) virus, were assessed. Two doses of mRNA vaccination elicited robust neutralizing antibody titers against a 2022 avian isolate and a 2024 human isolate. Further, mRNA vaccination conferred protection from lethal challenge, whereas all unvaccinated ferrets succumbed to infection. It also reduced viral titers in the upper and lower respiratory tracts of infected ferrets. These results underscore the effectiveness of mRNA vaccines against HPAI A(H5N1), showcasing their potential as a vaccine platform for future influenza pandemics.

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#Surveillance #Strategy in #Duck Flocks Vaccinated against Highly Pathogenic Avian #Influenza Virus

Abstract

Since 2016, epizootics of highly pathogenic avian influenza (HPAI) virus have threatened the poultry sector in Europe. Because conventional prevention and control measures alone were insufficient in some contexts, the European Commission authorized poultry vaccination in 2023. Subsequently, France launched a nationwide duck vaccination campaign combined with a comprehensive surveillance plan. We used a mathematical model to simulate the transmission of HPAI viruses in vaccinated duck flocks and assess the effectiveness of a wide range of surveillance strategies. Sampling and testing dead ducks every week (enhanced passive surveillance) was the most sensitive (≈90%) and the most timely strategy. Active surveillance through monthly testing of a cross-sectional sample of live ducks was the least sensitive and timely strategy. Thus, we advise focusing HPAI surveillance efforts on enhanced passive surveillance and reducing active surveillance of live ducks.

Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/31/1/24-1140_article

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#USA confirms its first severe case of #H5N1 #flu - #California declares state of #emergency - #UN agencies warn: This epidemic "is increasingly crossing species barriers"

According to CCTV News, on December 18 local time, California Governor Gavin Newsom declared a state of emergency in California to deal with the increasingly serious avian influenza epidemic.

Although there have been no cases of human-to-human transmission in California, 61 people have been infected with avian influenza in the United States, 34 of which are from California. Newsom emphasized that although the risk is low, the government will continue to take necessary measures to prevent the spread of the virus and open funds to support the emergency response of relevant agencies.

According to Xinhua News Agency, the U.S. Centers for Disease Control and Prevention issued a statement on the 18th saying that the United States reported the first severe case of human infection with the H5N1 avian influenza virus . The patient was hospitalized and his infection may be related to contact with sick and dead poultry raised in private backyard farms.

The CDC said in a statement that the patient was from Louisiana, and was diagnosed with the H5N1 avian influenza virus on the 13th. The investigation into the source of infection is still ongoing, but it can be confirmed that the patient had contact with sick and dead poultry raised in a private backyard farm. This is also the first case of human infection with the H5N1 avian influenza virus in the United States related to a private backyard farm.

Preliminary genetic analysis results show that the avian influenza virus that infected the patient belongs to the D1.1 type. The CDC is conducting further genome sequencing on the virus samples.

According to the data from the US Centers for Disease Control and Prevention, since April this year, a total of 61 cases of human infection with the H5 avian influenza virus have been reported in the United States. The agency said that it is not surprising that some people have been seriously ill with the H5N1 avian influenza. Previously, other countries have reported cases of severe illness or death from human infection with the H5N1 avian influenza. So far, no human-to-human transmission of the H5 avian influenza virus has been found. The direct risk to public health posed by the H5N1 avian influenza is still low.

The CDC reminds the public to avoid contact with sick or dead animals, especially wild birds and poultry, as much as possible. Individuals who have direct or close contact with wild birds or sick, dead poultry and other animals need to wear protective equipment.

According to a report by Xinhua News Agency on November 7, a new study conducted by researchers from the US Centers for Disease Control and Prevention and other institutions showed that the actual number of US dairy farm workers infected with the highly pathogenic H5N1 avian influenza virus may far exceed official statistics. The relevant research report was published in the US Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Journal.

From June to August 2024, researchers collected and tested blood samples from workers on dairy farms in Michigan and Colorado, where outbreaks of highly pathogenic H5N1 avian influenza had occurred. They found that 8 of the 115 workers tested had recently been infected with the H5N1 avian influenza virus, with an infection rate of 7%.

Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security in the United States, said that thousands of dairy workers may have been exposed to infected dairy cows, and the new study shows that many cases have been missed. She believes that it is likely that most or all states with H5N1 avian influenza outbreaks have human cases.

Since March this year, the H5N1 avian influenza virus has continued to spread in the United States. According to the latest statistics from the U.S. Department of Agriculture, the H5N1 avian influenza virus has been detected in more than 440 dairy cow herds in 15 states in the United States.

In response to the latest findings, the CDC is expanding testing of affected dairy farm workers. The agency is also recommending that workers who have had high-risk contact with infected animals take antiviral drugs.

According to Cankaoxiaoxi.com, Reuters reported on October 31 that bird flu has spread rapidly among poultry in many EU countries this season, raising concerns about a repeat of the crisis. Previous bird flu outbreaks have killed tens of millions of poultry in many EU countries, and people are also worried that bird flu could be transmitted to humans.

The UK Department for Environment, Food and Rural Affairs announced on December 17 that cases of highly pathogenic avian influenza were confirmed in two breeding farms in Norfolk. The animal health department decided to kill the poultry in the farms and designate protection and monitoring areas.

The Food and Agriculture Organization of the United Nations (FAO), the World Organization for Animal Health and other organizations warned at a briefing at the United Nations Office in Geneva on the 17th that the avian influenza epidemic sweeping the world "is increasingly crossing species barriers . "

Gregorio Torres, director of the Scientific Department of the World Organization for Animal Health, said that since October 2021, the avian influenza epidemic has killed more than 300 million poultry worldwide. The virus is increasingly crossing species barriers, infecting poultry and wild mammals, causing serious impacts on the ecosystem.

FAO official Madhur Dingra also pointed out that the impact of the highly pathogenic avian influenza virus has spread to wild animals, infecting more than 500 species of birds and more than 70 species of mammals, including endangered animals such as polar bears.

Source: SINA, https://news.sina.com.cn/w/2024-12-19/doc-inczynpw0156337.shtml

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#USA, DHS Reports Presumptive Positive #Human Case of Highly Pathogenic Avian #Influenza (#H5N1) in #Wisconsin

{Excerpt}

The Wisconsin Department of Health Services (DHS) has detected the first presumptive positive human case of Highly Pathogenic Avian Influenza A (H5N1), also known as bird flu, in Barron County. The human case follows an infected flock of commercial poultry identified in Barron County. The person had exposure to the infected flock. The case was identified through testing at the Wisconsin State Lab of Hygiene (WSLH) and is pending confirmation at CDC (Centers for Disease Control and Prevention).

DHS, in coordination with Barron County Health and Human Services, is monitoring farm workers who may have been exposed to the virus and has provided them with information to protect their health. The risk to the general public in Wisconsin remains low. People who work with infected animals, or have recreational exposure to them, are at higher risk.

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Source: Department of Health, https://www.dhs.wisconsin.gov/news/releases/121824.htm

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#USA, #CDC Confirms First Severe Case of #H5N1 #Birdflu in the United States

December 18, 2024-- A patient has been hospitalized with a severe case of avian influenza A(H5N1) virus ("H5N1 bird flu") infection in Louisiana. 

This marks the first instance of severe illness linked to the virus in the United States. The case was confirmed by the Centers for Disease Control and Prevention (CDC) on Friday, December 13. 

Since April 2024, there have been a total of 61 reported human cases of H5 bird flu reported in the United States.

Partial viral genome data of the H5N1 avian influenza virus that infected the patient in Louisiana indicates that the virus belongs to the D1.1 genotype related to other D1.1 viruses recently detected in wild birds and poultry in the United States and in recent human cases in British Columbia, Canada, and Washington state. This H5N1 bird flu genotype is different than the B3.13 genotype detected in dairy cows, sporadic human cases in multiple states, and some poultry outbreaks in the United States. Additional genomic sequencing and efforts to isolate virus from clinical specimens from the patient in Louisiana are underway at CDC.

While an investigation into the source of the infection in Louisiana is ongoing, it has been determined that the patient had exposure to sick and dead birds in backyard flocks. This is the first case of H5N1 bird flu in the U.S. that has been linked to exposure to a backyard flock. A sporadic case of severe H5N1 bird flu illness in a person is not unexpected; avian influenza A(H5N1) virus infection has previously been associated with severe human illness in other countries during 2024 and prior years, including illness resulting in death. No person-to-person spread of H5 bird flu has been detected. This case does not change CDC's overall assessment of the immediate risk to the public's health from H5N1 bird flu, which remains low.

This case underscores that, in addition to affected commercial poultry and dairy operations, wild birds and backyard flocks also can be a source of exposure. People with work or recreational exposures to infected animals are at higher risk of infection and should follow CDC's recommended precautions when around animals that are infected or potentially infected with H5N1 avian influenza virus. This means that backyard flock owners, hunters and other bird enthusiasts should also take precautions.

The best way to prevent H5 bird flu is to avoid exposure whenever possible. Infected birds shed avian influenza A viruses in their saliva, mucous, and feces. Other infected animals may shed avian influenza A viruses in respiratory secretions and other bodily fluids (e.g., in unpasteurized cow milk or 'raw milk').

As a general precaution, whenever possible, people should avoid contact with sick or dead animals, in particular wild birds, and poultry.

For individuals with direct/close contact with wild birds or sick or dead poultry or other animals, wear recommended personal protective equipment (PPE). Wild birds can be infected with avian influenza A viruses even if they don't look sick.

-- Do not touch surfaces or materials (e.g., animal litter or bedding material) contaminated with saliva, mucous, or animal feces from wild or domestic birds or other animals with confirmed or suspected avian influenza A virus infection.

For more information on H5 bird flu in the U.S. and CDC's response, including regularly updated case counts, visit the H5 Bird Flu: Current Situation page.

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/media/releases/2024/m1218-h5n1-flu.html

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Avian #influenza: increased spread in #poultry-dense areas at end 2024

 {Excerpt}

Abstract 

Between 21 September and 6 December 2024, 657 highly pathogenic avian influenza (HPAI) A(H5N1) and A(H5N5) virus detections were reported in domestic (341) and wild (316) birds across 27 countries in Europe. Many HPAI outbreaks in domestic birds were clustered in areas with high poultry density and characterised by secondary farm-to-farm spread. Waterfowl, particularly the mute swan, were primarily affected during this reporting period, with HPAI virus detections focused on south-eastern Europe. Notably, A(H5N5) viruses expanded their geographic and host range, resulting in a surge in detections and mortality events described in gulls and crows. No new HPAI virus detections in mammals were reported in Europe during this reporting period, but the number of dairy cattle farms reportedly affected in the United States of America (USA) rose to > 800 in 16 States, and HPAI virus was identified in two pigs in a mixed-species farm. Between 21 September and 11 December 2024, 56 new human cases with avian influenza virus infection were reported from North America (45 A(H5N1) cases), Viet Nam (one A(H5)) and China (ten A(H9N2) cases). Most of the A(H5) human cases in North America (95.6%, n = 43/45) had reported exposure to poultry, live poultry markets, or dairy cattle prior to avian influenza virus detection or onset of illness. Human infections with avian influenza viruses remain rare and no evidence of human-to-human transmission has been documented in the reporting period. The risk of infection with currently circulating avian A(H5) influenza viruses of clade 2.3.4.4b in Europe remains low for the general public in the European Union/European Economic Area (EU/EEA). The risk of infection remains lowto-moderate for those occupationally or otherwise exposed to infected animals or contaminated environments. 

©2025 European Food Safety Authority, European Centre for Disease Prevention and Control, European Union Reference Laboratory for Avian Influenza. EFSA Journal published by Wiley-VCH GmbH on behalf of European Food Safety Authority. 

Source: European Food Safety Authority, https://www.efsa.europa.eu/sites/default/files/2024-12/9204.pdf

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Detection of #Prions in Wild #Pigs (Sus scrofa) from Areas with Reported #CWD Cases, #USA

Abstract

Using a prion amplification assay, we identified prions in tissues from wild pigs (Sus scrofa) living in areas of the United States with variable chronic wasting disease (CWD) epidemiology. Our findings indicate that scavenging swine could play a role in disseminating CWD and could therefore influence its epidemiology, geographic distribution, and interspecies spread.

Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/31/1/24-0401_article

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#USA, Confirmed #human case of #H5N1 #influenza summary during 2024 #outbreak, by state and exposure source {as of Dec. 17 '24: +1 case, total now = 61}

 {Excerpt}

Exposure Source

[State - Exposure Associated with Commercial Agriculture and Related Operations: Dairy Herds (Cattle) - Poultry Farms and Culling Operations - Other Animal Exposure† - Exposure Source Unknown‡ - State Total]

1) California - 33 - 0 - 0 - 1 - 34

2) Colorado - 1 - 9 - 0 - 0 - 10

3) Louisiana - 0 - 0 - 1 - 0 - 1 {+1}

4) Michigan - 2 - 0 - 0 - 0 - 2

5) Missouri - 0 - 0 - 0 - 1 - 1

6) Oregon - 0 - 1 - 0 - 0 - 1

7) Texas - 1 - 0 - 0 - 0 - 1

8) Washington - 0 - 11 - 0 - 0 - 11

-- Source Total - 37 - 21 - 1 - 2 - 61 {+1}

NOTE: One additional case was previously detected in a poultry worker in Colorado in 2022.

{†} Exposure was related to other animals such as backyard flocks, wild birds, or other mammals

{‡} Exposure source was not able to be identified

Additional cases meeting the Council of State and Territorial Epidemiologists (CSTE) probable case definition have been reported by states: 

-- 1 case with dairy cow exposure (CA), 

-- 3 cases with poultry exposure (WA), and 

-- 2 cases with poultry exposure (AZ) and 

-- 1 case with no defined exposure (DE). 

Confirmatory testing at CDC for these cases was negative.

This table is typically updated by 5 PM EST on Mondays (for cases confirmed by CDC on Friday, Saturday, or Sunday), Wednesdays (for cases confirmed by CDC on Monday or Tuesday), and Fridays (for cases confirmed by CDC on Wednesday and Thursday). Affected states may report cases more frequently. This table was last updated on Tuesday, December 17, 2024, outside of CDC’s routine posting cadence.

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Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/bird-flu/situation-summary/?CDC_AAref_Val=https://www.cdc.gov/flu/avianflu/avian-flu-summary.htm 

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Meta-Analysis of #Seroprevalence and #Prevalence of #Influenza A Viruses (Subtypes #H3N2, #H3N8, and #H1N1) in #Dogs

Abstract

Influenza A is a zoonotic disease that affects dogs, pigs, horses, poultry, and birds. In this report, a meta-analysis according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) was conducted. Studies of influenza A viruses in dogs providing prevalence or seroprevalence in any location worldwide were included. The results in this study show that the seroprevalence for the H3N8 influenza subtype was 7.96% (95% CI: 2.03–16.8, p < 0.001), for the H3N2 subtype was 7.44% (95% CI: 4.51–10.5, p < 0.001), and for the H1N1 subtype was 3.10% (95% CI: 0.890–6.01, p < 0.001). In the case of the prevalence analysis, a prevalence of 0.395% (95% CI: 0.160–2.44) for the H3N8 subtype. For the H3N2 subtype, a prevalence of 17.8% (95% CI: 6.66–32.6, p < 0.001) was found. No publication bias was observed in the studies evaluating seroprevalence in the H3N2 and H1N1 subtypes. In the H3N8 subtype, Begg’s test indicated publication bias, but Egger’s test showed no bias. It is essential to know the approximate prevalence and seroprevalence worldwide of canine influenza, so this study reports the presence of influenza subtypes in dogs, placing this species as a reservoir for human, swine, equine, and avian influenza A viruses.

Source: Animals (Basel), https://www.mdpi.com/2076-2615/14/23/3467 

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Avian #flu reported in 108 countries across five #continents, says #UN health agency

In an update on the mutating virus - known as H5N1 – Dr. Madhur Dhingra from the Food and Agriculture Organization, FAO, said that it had “spilled over into wildlife”. 

More than 500 bird species have been infected along with at least 70 mammalian species, including the endangered California condor and polar bears. 

In regions that are heavily reliant on poultry as a primary source of protein, the FAO medic insisted that avian influenza “poses a serious threat to food and nutrition security”.

Economic damage

Dr Dhingra warned that hundreds of millions of people’s livelihoods have been affected by the virus – an economic burden on farmers that could prevent them from investing in adequate biosafety measures.

Following the emergence of H5N1 influenza virus in dairy cattle, the WHO has joined calls for strengthened surveillance and biosecurity on farms, to keep animals and people safe.

The UN health agency said that in 2024, 76 people have been infected with the H5 avian influenza strain, and most were farm workers. More than 60 cases originated in the US, which has also reported outbreaks of H5 in wildlife and poultry and, more recently, in dairy cattle.

There have also been cases reported in Australia, Canada, China, Cambodia and Viet Nam.

Low risk to humans – for now

Dr. Maria Van Kerkhove, who currently serves as Director of Epidemic and Pandemic Threat Management for the WHO, said that based on the latest science, “we assess the risk of infection for the public – you and I – is currently low.”

But if you work on a farm, she cautioned – and are exposed to infected animals – “we assess the current public health risk to be low-to-moderate,” depending on the level of personal protection taken.

There is no evidence so far that the H5N1 viruses have adapted to spread between people and there has been no reported cases of human-to-human transmission.

No room for complacency

“We must remember, however, that this can change quickly,” the UN pandemic expert added, “as the virus is evolving and we must be prepared for such a scenario.”

Every case that occurs in humans must therefore be investigated thoroughly.

Dr. Van Kerkhove also stressed the importance of drinking pasturised milk – and if that’s not available, of heating milk before consumption.

“We want to reiterate the critical importance of using a One Health approach across sectors – globally, nationally, and sub-nationally -  to tackle avian influenza effectively, to minimize the risk in animals and humans,” she concluded.  

Source: United Nations, https://news.un.org/en/story/2024/12/1158286 

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