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

Unspecified species of domestic birds in Sumy Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6251

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

 Two Greylag Goose, one Eurasian buzzard, two Eurasian Jackdaw, one Whooper Swan, one Common Guineafowl in Northern Ireland.

Source: WOAH, https://wahis.woah.org/#/in-review/6248

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#USA, Confirmed #human #H5N1 #influenza virus case #summary since 2024, by state and exposure source: One new case in #Nevada (Feb. 10 '25)

{Excerpt}

[State - Exposure Source: 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 - 36 - 0 - 0 - 2 - 38

2) Colorado - 1 - 9 - 0 - 0 - 10

3) Iowa - 0 - 1 - 0 - 0 - 1

4) Louisiana - 0 - 0 - 1 - 0 - 1

5) Michigan - 2 - 0 - 0 - 0 - 2

6) Missouri - 0 - 0 - 0 - 1 - 1

7) Nevada - 1 - 0 - 0 - 0 - 1 {+1}

8) Oregon - 0 - 1 - 0 - 0 - 1

9) Texas - 1 - 0 - 0 - 0 - 1

10) Washington - 0 - 11 - 0 - 0 - 11

11) Wisconsin - 0 - 1 - 0 - 0 - 1

-- Source Total - 41 - 23 - 1 - 3 - 68 {+1}

NOTE: One additional case was previously detected in a poultry worker in Colorado in 2022. Louisiana reported the first H5 bird flu death in the U.S.

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

{‡} Exposure source was not able to be identified

Probable human case summary during the 2024 outbreak, by state and exposure source

When a case tests positive for H5 at a public health laboratory but testing at CDC is not able to confirm H5 infection, per Council of State and Territorial Epidemiologists (CSTE) guidance, a case is reported as probable.

-- Probable cases with commercial poultry exposure (e.g., poultry farms or culling operations):

1) Washington (3)

2) Arizona (2)

-- Probable cases with commercial dairy (cattle) exposure:

1) California (1)

-- Probable cases with exposure source unknown:

1) Delaware (1)

Confirmed and probable cases are 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.

(...)

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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Novel #H16N3 avian #influenza viruses isolated from migratory #gulls in #China in 2023

Abstract

As a rare subtype of avian influenza virus, H16 viruses are predominant in gulls but rarely found in domestic birds. The low prevalence of H16 viruses has limited our understanding of their epidemiology and evolutionary dynamics. In this study, we isolated three novel H16N3 viruses from migratory gulls in East Asian–Australasian Flyway in eastern China in 2023, which are significantly different from previously identified isolates. To fully understand the epidemiology and genetics characteristics of the global H16 viruses, we compared the host divergence of several rare subtypes and determined that the H13 and H16 subtypes were predominantly pooled into different species of gulls by sharing their internal genes, whereas the waterfowl of Anatidae served as the primary natural reservoirs of the H8, H11, H12, H14, and H15 subtypes. Detailed phylogenetic analysis revealed the evolutionary divergence of globally circulating H16 viruses and their frequent gene reassortment. Furthermore, the gull origin H13 and H16 viruses collectively served as gene donors for the newly emerged highly pathogenic clade 2.3.4.4b H5N1 viruses because the H13/H16-like PA, NP, and NS genes have been introduced into circulating H5N1 viruses since May 2022 in Europe. To date, the H5N1 reassortants containing the H13/H16-like gene segments have been detected in wild and domestic birds and resulted in mammal and human infections. These results improve our knowledge of the ecology and genetics of H16 viruses and emphasize the need for surveillance to monitor the emergence of novel avian influenza viruses in migratory birds.

Source: Frontiers in Microbiology, https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1543338/full

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Reduction of #Influenza A Virus #Prevalence in #Pigs at Weaning After Using Custom-Made Influenza #Vaccines in the Breeding #Herds of an Integrated Swine #Farm System

Abstract

Vaccination is a common influenza A virus (IAV) control strategy for pigs. Vaccine efficacy depends on strain cross-protection and effective vaccination program implementation. We evaluated a multi-faceted IAV vaccination strategy which included (a) monthly surveillance of pigs at weaning, (b) selection of epidemiologically relevant strains from farms under surveillance, (c) updating IAV strains in custom-made vaccines, and (d) seasonal mass vaccination with custom-made vaccines given to sows in 35 farrow-to-wean farms within an integrated swine farm system. Reduction of IAV in pigs from vaccinated sows was determined by monthly monitoring of farms for 30 months by IAV rRT-PCR (PCR) testing of nasal wipes collected from litters of piglets at weaning. Hemagglutinin (HA) nucleotide and amino acid (AA) sequence homology of the circulating and vaccine strains was determined by pairwise alignment and AA comparison at antigenic sites. Of the 35 farms monitored, 28 (80%) tested positive at least once, and 481 (5.75%) of 8352 PCR tests were IAV positive. Complete HA sequences were obtained from 54 H1 (22 H1-δ_1B.2.1, 28 H1-γ_1A.3.3.3, and 4 H1-pdm_1A.3.3.2 clades) and 14 H3 (12 IV-A 3.1990.4.1 and 2 IV-B 3.1990.4.2 clades) circulating IAV strains. During the study, custom-made vaccines were updated three times (eight strains total) and administered to sows at five distinct time periods. The HA AA similarity between vaccine and circulating strains ranged from 95% to 99%; however, the 0 to 71% similarity at HA antigenic sites prompted the vaccine updates. Herd IAV prevalence decreased from 40% (14/35) to 2.9% (1/35), accompanied by a numerical reduction in IAV-positive samples post-vaccination. Our results support having a comprehensive approach to controlling influenza in swine herds that includes surveillance, vaccination, and careful program implementation to reduce IAV in pigs.

Source: Viruses, https://www.mdpi.com/1999-4915/17/2/240

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South #Sudan declares #mpox #outbreak

Juba, 7 February 2025—Today the Ministry of Health has declared a mpox outbreak in Juba, Central Equatoria State. This declaration follows a confirmation mpox Case by the National Public Health Laboratory on 6 February 2025.

“The first case was reported on 6 February 2025 at Gudele Hospital from a Ugandan national and a resident of Kupuri Camp in Juba. The confirmed case is under isolation and is being managed at Gudele Hospital”, said the Acting Health Minister, Honorable James Hoth Mai, in a press conference in Juba. 

A team of experts from national and subnational levels, WHO, and other partners have been mobilized to conduct a detailed field investigation, list all contacts, and ensure close follow-up, Hon. Mai added.

He also added that the Ministry of Health and WHO have taken steps to manage the reported case properly, ensuring that every contact on the ground is followed. He assured the citizens not to panic but to stay calm and follow safety measures that the government is committed to stopping the spread of mpox in South Sudan.

Addressing the press conference, Dr Humphrey Karamagi, WHO Country  Representative in South Sudan, commended the Ministry of Health for declaring the outbreak. 

The announcement enables the public to take prevention measures, helps health partners take the necessary steps to contain the outbreak, and unlocks the required resources for fighting the outbreak. 

The confirmation of mpox in South Sudan showcases the national capabilities that WHO is proud to have significantly supported, said Dr Karamagi.

With this outbreak, South Sudan becomes the 22nd country to be affected in the African region. After this confirmation, my team will support the referral of the positive sample to WHO-collaborating laboratories for sequencing and genetic characterization of the Mpox virus detected in the country.

Dr Karamagi further reiterated WHO’s commitment to assisting the South Sudanese government and partners in enhancing disease surveillance, improving response coordination, and ensuring the availability of supplies. This includes supporting case management, laboratory testing, sample collection, transportation, and follow-up.

“Thanks to funding from our donors, WHO deployed experts and provided technical and logistical support,” said Dr Karamagi.

With the support of WHO, the Ministry has activated the Public Health Emergency Operations Center and prepared to coordinate responses to Mpox outbreaks, following the WHO guidelines. 

An Incident Manager and key health officials have been assigned to monitor five main entry points into South Sudan for suspected Mpox cases from high-risk neighboring countries like the Democratic Republic of the Congo (DRC), Uganda, and Kenya. 

All healthcare providers, including those in private practice, are receiving training on recognizing and responding to Mpox symptoms. We are developing a laboratory network and have tested samples from 141 suspected cases. 

New testing methods have been implemented, guaranteeing accurate results via external quality checks. 

Recent tests showed a 100% success rate, and our laboratory excelled in proficiency assessments. Moreover, 40 clinicians have received training in Mpox case management to ensure effective treatment and bolster our readiness for any possible Mpox outbreaks in South Sudan.

The Hon. Minister also urged the communities to practice good and safe behaviors, such as avoiding close contact with an infected person, using personal protective equipment when caring for patients, not sharing bedding, clothing, towels, or utensils with sick people, practicing hand hygiene and respiratory etiquette, isolate infected patients, avoid contact with wild animals and cook all food containing fresh animal meat before eating.

He urged health workers to remain vigilant with high index suspicious for mpox, adhere to infection prevention and control measures, follow standard operating procedures, and report suspected cases for further investigation. 

The press conference was attended by the media, high-level government officials, and partners, among others.

Source: World Health Organization, Regional Office for Africa, https://www.afro.who.int/countries/south-sudan/news/south-sudan-declares-mpox-outbreak

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Christ and the Woman taken in Adultery, Pieter Bruegel the Elder (c.1565)

 Public Domain.

Source: WikiArt, https://www.wikiart.org/en/pieter-bruegel-the-elder/christ-and-the-woman-taken-in-adultery-1565-1

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Limited #transmission of avian #influenza viruses, #avulaviruses, #coronaviruses and #Chlamydia sp. at the interface between wild #birds and a free-range duck #farm

Abstract

Recent outbreaks of highly pathogenic avian influenza in Europe have raised questions regarding the epidemiological role of commensal wild birds on free-range poultry farms. This study aimed to assess the prevalence of avian influenza viruses (AIV), avulaviruses, coronaviruses and Chlamydia sp. in commensal wild birds on a free-range duck farm in southwestern France and to evaluate possible transmission events at the wild‒domestic interface. From 2019 through 2021, a longitudinal study was conducted on wild birds, domestic ducks and their shared environment on farms. Commensal wild birds were captured and sampled for blood and swabs, and fresh feces from cattle egrets visiting the farm were collected. In parallel, domestic ducks were sampled, and environmental samples were collected. The presence of the four pathogens was tested by q(RT-)PCR, and the immunity of wild birds to AIV and Newcastle disease virus (NDV) was tested by ELISA. Wild birds were found to shed AIV and Chlamydia only, with a low prevalence (< 3%). The seroprevalence rates were less than 10% for AIV and less than 4.5% for NDV. No significant temporal trend was identified. Ducks and their environment frequently test simultaneously positive for the same pathogens (19 to 44% of flocks), mostly during fall‒winter. In addition to unrelated temporal patterns, the identification of pathogens in wild birds seemed unrelated to that in domestic ducks. These results suggest a low transmissibility of the avian pathogens tested in our study at the wild‒domestic interface and highlight the limited contribution of commensal wild birds in comparison with free-range poultry to the global microbiological pressure on the environment.

Source: Veterinary Research, https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-025-01466-3

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#Pathology of #Influenza A (#H5N1) #infection in #pinnipeds reveals novel tissue #tropism and vertical #transmission.

Abstract

In 2023, an unprecedented outbreak of highly pathogenic avian influenza (HPAI) H5N1 resulted in the death of thousands of pinnipeds along the Argentinean coast, raising concerns about its ecological and epidemiological impact. Here, we present clinical, pathological, and molecular findings associated with HPAI H5N1 infection in pinnipeds from Chubut, Argentina. Necropsies were conducted on three South American Sea Lions (SASLs) (Otaria flavescens) and one Southern Elephant Seal (SES) (Mirounga leonina), followed by histopathological, immunohistochemical and RT-sqPCR analyses. Neurological clinical signs were observed in two SASLs, with one also exhibiting respiratory distress. Neuropathological findings included lymphoneutrophilic meningoencephalomyelitis and choroiditis, neuronal necrosis, gliosis, hemorrhages, and perivascular cuffing. Viral antigen was localized in neurons, glial cells, choroid plexus epithelial cells, ependymal cells, and the neuropil. Systemic manifestations included HPAI-related necrotizing myocarditis in the elephant seal and placental necrosis in a sea lion, with fetal tissues testing positive for HPAIV. Pulmonary lesions were minimal, limited to bronchial glands in one individual. RT-sqPCR confirmed HPAI H5 in all tested animals. Our findings highlight the neurotropism of HPAI H5N1 in pinnipeds, and expand the known systemic effects of the virus, revealing new tissue tropism and vertical transmission.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.02.07.636856v1

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{#USA, #Nevada} The Occurrence of Another Highly Pathogenic Avian #Influenza (HPAI) #Spillover from Wild #Birds into Dairy #Cattle

Background  

In March 2024, the USDA confirmed the first case of highly pathogenic avian influenza (HPAI) spreading between dairy cattle herds in the United States. 

This followed reports from dairy producers of an unusual illness in their lactating cows over the preceding 2-3 months. 

Virus whole genome sequencing and modeling performed by USDA suggested a single spillover of HPAI H5N1, clade 2.3.4.4b, genotype B3.13 from wild birds into dairy cattle likely occurred between October 2023 and January 2024 (1). 

Since then, federal, state, and industry partners have collaborated to address the HPAI threat in dairy cattle, resulting in two federal orders and the implementation of the National Milk Testing Strategy (NMTS). 

States began enrolling in the NMTS in December 2024, in which they are continuing to conduct or now implementing state-wide bulk tank surveillance and/or milk processing plant silo monitoring. 

Nevada was among the first to participate in the National Silo Monitoring Program, which includes testing milk samples from processing plant silos for HPAI. 

This sampling scheme coincides with the FDA's existing regulatory program, which requires all raw milk Grade A silos to be sampled four times within 6 months. 

The Detection In Nevada, 3 of 11 silo samples collected on January 6 and 7, 2025 tested positive for HPAI via polymerase chain reaction (PCR) at the National Veterinary Services Laboratories (NVSL) on January 10. 

The state was notified, triggering an investigation to trace the source, as up to  12 dairies (in the same geographic region) could have contributed milk to the affected silos. 

On January 17, regulatory officials collected on-farm bulk milk samples from suspected dairy farms and submitted them to the Washington Animal Disease Diagnostic Laboratory (WADDL), a member of the National Animal Health Laboratory Network (NAHLN). 

HPAI was confirmed via PCR at NVSL on Friday, January 24, in samples from two of those dairies. 

NVSL completed whole genome sequencing on January 31 and identified HPAI H5N1, clade 2.3.4.4b, genotype D1.1 in samples from four different bulk tanks from one herd. 

A second herd also showed a partial sequence consistent with D1.1. 

Clinical signs were not observed in the cattle prior to the detection, but have been reported since, and the affected dairy producers reported large wild bird die-offs near the dairies. 

While genotype D1.1 has been the dominant strain circulating in migratory wild birds across all four North American flyways during the winter of 2024-2025, these Nevada cases represent the f irst detection of a genotype other than B3.13 in U.S. dairy cattle and the second known spillover from wild birds into lactating dairy cattle. 

Virus Epidemiology and Origin 

Since late 2021, six separate introductions of Eurasian HPAI H5N1 clade 2.3.4.4b have been documented into the migratory wild birds in the North American flyways (genotypes A1 through A6). 

Genotype D1.1 is a reassortant of A3. Genotype A3 first appeared in the Pacific flyway in April of 2022 with detections only in the Pacific flyway until the fall of 2024. 

Since this fall, genotype A3 has been sporadically reported in migratory wild birds across all four flyways through wild bird surveillance, making up 3.3% of the overall detections to date. 

Genotype D1.1 retains four genes from the original A3 genotype; hemagglutinin (HA), polymerase basic 1 (PB1), matrix (M) and nonstructural (NS), with other genes originating from other North American lineage viruses found in migratory wild birds. 

This genotype was first detected in September 2024 and has quickly expanded to all North American flyways. 

D1.1 is the current predominant genotype in migratory wild birds, making up 6.07% of the total detections since 2022 despite f irst occurring late 2024. 

The D1.1 viruses identified in dairy cattle in Nevada were found to be closely related to other D1.1 viruses recently detected in migratory wild birds across multiple North American Flyways. 

Analysis of the hemagglutinin gene of the Nevada dairy cattle viruses did not identify changes predicted to impact infectivity or adaptation to mammalian hosts. 

However, a change of PB2 D701N commonly associated with mammalian adaptation of HPAI virus was identified in viruses sequenced from four separate dairy cattle. 

To date, this change has not been observed in D1.1 viruses found in wild birds or poultry and is not found in B3.13 genotype viruses detected in dairy cattle. 

PB2 D701N has previously been associated with mammalian adaptation because it improves RNA polymerase activity and replication efficiency in mammalian cells and has the potential to impact pathogenesis in infected mammals (2,3,4,5,6). 

The change has previously been identified in human cases of HPAI H5 but with no evidence of onward transmission among humans (7,8). 

No other changes associated with mammalian adaptation were identified in the sequences. 

Of note, these D1.1 viruses sequenced from dairy cattle do not contain the PB2 631L marker that appeared to be fixed in dairy cattle B3.13 sequences. 

Following the existing public sharing process, NVSL immediately provided the D1.1 sequence information the Centers for Disease Control and Prevention and will post sequence files to the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA) within 7 days of analysis, adding metadata as sequences are interpreted and quality checked in light of epidemiological information.   

Summary 

This detection indicates that this HPAI virus, genotype D1.1, is the second spillover event from migratory wild birds to dairy cattle following the B3.13 event in late 2023/early 2024. 

Investigations are ongoing to fully characterize this event. The Nevada Department of Agriculture acted quickly, by first rapidly enrolling in the NMTS to initiate active surveillance, and then to identify and quarantine the affected dairies before cattle movements could further transmit this virus beyond the local area. 

This is the first instance where sampling of milk at processing plants rather than individually or directly on farm has detected a high consequence disease, demonstrating silo monitoring as an efficient method to monitor HPAI in the National dairy herd.  

1. Nguyen T, Hutter C, Markin A, Thomas M, Lantz K, Killian M, Janzen GM, Vijendran S, Wagle S, Inderski B, Magstadt DR, Li G, Diel DG, Frye EA, Dimitrov SM, Swinford A, Thompson AC, Snevik KR, Suarez DL, Spackman E, Lakin S, Ahola SC, Johnson SR, Baker A, Robbe-Austerman S, Torchetti M, Anderson TK. 2024. Emergence and interstate spread of highly pathogenic avian influenza A(H5N1) in dairy cattle. bioRxiv 2024.05.01.591751; doi: https://doi.org/10.1101/2024.05.01.591751 

2. Li Z, Chen H, Jiao P, Deng G, Tian G, Li Y, Hoffmann E, Webster RG, Matsuoka Y, Yu K. 2005. Molecular basis of replication of duck H5N1 influenza viruses in a mammalian mouse model. The Journal of Virology 79:12058-12064. 

3. Gabriel G, Abram M, Keiner B, Wagner R, Klenk HD, Stech J. 2007. Differential polymerase activity in avian and mammalian cells determines host range of influenza virus. J Virol 81:9601-4. 

4. Steel J, Lowen AC, Mubareka S, Palese P. 2009. Transmission of influenza virus in a mammalian host is increased by PB2 amino acids 627K or 627E/701N. PLoS Pathog 5:e1000252. 

5. Gao Y, Zhang Y, Shinya K, Deng G, Jiang Y, Li Z, Guan Y, Tian G, Li Y, Shi J, Liu L, Zeng X, Bu Z, Xia X, Kawaoka Y, Chen H. 2009. Identification of amino acids in HA and PB2 critical for the transmission of H5N1 avian influenza viruses in a mammalian host. PLoSPathog 5:e1000709. 

6. Zhou B, Pearce MB, Li Y, Wang J, Mason RJ, Tumpey TM, Wentworth DE. 2013. Asparagine substitution at PB2 residue 701 enhances the replication, pathogenicity, and transmission of the 2009 pandemic H1N1 influenza A virus. PLoS ONE 8:e67616. 

7. Le QM, Ito M, Muramoto Y, Hoang PV, Vuong CD, Sakai-Tagawa Y, Kiso M, Ozawa M, Takano R, Kawaoka Y. 2010. Pathogenicity of highly pathogenic avian H5N1 influenza A viruses isolated from humans between 2003 and 2008 in northern Vietnam. J Gen Virol 91:2485-90.  

8. Zhu W, Li X, Dong J, Bo H, Liu J, Yang J, Zhang Y, Wei H, Huang W, Zhao X, Chen T, Yang J, Li Z, Zeng X, Li C, Tang J, Xin L, Gao R, Liu L, Tan M, Shu Y, Yang L, Wang D. 2022. Epidemiologic, Clinical, and Genetic Characteristics of Human Infections with Influenza A(H5N6) Viruses, China. Emerg Infect Dis 28:1332-1344. 

Source: US Department of Health, https://www.aphis.usda.gov/sites/default/files/dairy-cattle-hpai-tech-brief.pdf

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#USA, Monitoring for Avian #Influenza A(#H5) Virus In #Wastewater {Jan. 7 '25)

 {Excerpt}

Time Period: January 26 - February 01, 2025

-- H5 Detection: 17 sites (4.9%)

-- No Detection: 331 sites (95.1%)

-- No samples in last week: 51 sites

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Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/bird-flu/h5-monitoring/index.html

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#USA, One #human infection with #H1N2 #variant #influenza virus has been reported by #Iowa

{Excerpt}

Novel Influenza A Virus Infections

One human infection with influenza A(H1N2) variant (A(H1N2)v) virus was reported by the Iowa Department of Health and Human Services.

The patient is ≥18 years of age and sought health care during the week ending January 18, 2025 (Week 3), was hospitalized, and has recovered from their illness. 

An investigation by state public health officials did not identify direct or indirect swine contact by the patent. 

No illness was identified among the patient's close contacts. 

No human-to-human transmission has been identified associated with this case.

This is the first human infection with a variant influenza virus reported during the 2024-2025 season in the United States.

When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a "variant" influenza virus. 

Most human infections with variant influenza viruses occur following exposure to swine, but human-to-human transmission can occur. 

It is important to note that in most cases, variant influenza viruses have not shown the ability to spread easily and sustainably from person to person. 

Additional information on influenza in swine, variant influenza virus infection in humans, and guidance to interact safely with swine can be found at www.cdc.gov/flu/swineflu/index.htm.

No new human infections with A(H5) were reported to CDC this week. An ongoing outbreak of H5N1 continues in domestic dairy cows and poultry, and monitoring for additional human cases is ongoing.

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 A(H5) case summary during the 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.

(...)

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/fluview/surveillance/2025-week-05.html

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#USA, After #Birdflu Detected in Local #Cat, County #Health Officials Say #Pet Owners Should Contact Veterinarian When Their Pets are Sick

Redwood City — State veterinary and health officials have confirmed a case of H5N1 (bird flu) in a domestic stray cat in San Mateo County. 

The infection, which is not related to the recent instance of bird flu in a backyard flock, was found in a stray cat in Half Moon Bay that had been taken in by a family. 

When it showed symptoms, they took it to Peninsula Humane Society, whose veterinarians examined it and requested testing. Lab results confirmed H5N1. 

It is not known how the cat was infected and it was euthanized due to its condition.

Cats may be exposed to bird flu by consuming infected bird, being in environments contaminated with the virus and consuming unpasteurized milk from infected cows or raw food. Inside domestic animals, such as cats and dogs, that go outside are also at risk of infection.​​​​​​​

According to the Centers for Disease Control and Prevention, the risk of cats spreading H5N1 to people is extremely low, though it is possible for cats to spread some strains of bird flu to people.

While there are no human cases of H5N1 related to this case, this detection in a cat highlights the importance of being proactive about preventing the spread of the virus.

Residents whose pets show signs of illness should contact their veterinarian.

Pets infected with H5N1 may experience a loss of appetite, lethargy and fever, along with neurologic signs, including circling, tremors, seizures or blindness. The illness may quickly progress to:

-- Severe depression

-- Discharge from eyes or nose

-- Other respiratory signs, such as rapid shallow breathing, difficulty breathing and sneezing or coughing

-- Pets with severe illness may die.

If a pet is showing signs of illness consistent with bird flu and has been exposed to infected (sick or dead) wild birds or poultry, residents should contact a veterinarian and monitor their own health for signs of fever or infection.

“We all want to make sure our companion animals are healthy and safe from disease,” said Lori Morton-Feazell, San Mateo County’s chief of Animal Control and Licensing. “If your pet is sick, your veterinarian can determine whether it should be tested for bird flu or any other virus or disease.”

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Source: County of San Mateo, https://www.smcgov.org/ceo/news/after-bird-flu-detected-local-cat-county-health-officials-say-pet-owners-should-contact

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Highly Pathogenic Avian #Influenza Virus #H5N1 in Double-crested #Cormorants (Nannopterum auritum) of the #Chesapeake Bay, #USA

Abstract

Double-crested Cormorants (Nannopterum auritum) have historically exhibited low levels of infection and antibodies to avian influenza virus (AIV). The recent global expansion of clade 2.3.4.4b A/goose/Guangdong/1/1996 highly pathogenic (HP) avian influenza virus H5N1 (HPAI H5N1) has resulted in large-scale mortalities across diverse waterbird taxa including cormorants. We sampled 32 and 29 Double-crested Cormorants breeding in the Chesapeake Bay, US, during the summers of 2023 and 2024, respectively, to assess HPAI H5N1 infection and AIV antibodies. Although no mortality was observed in the area, one bird sampled in 2023 was infected with HPAI H5N1. Additionally, 21/31 individuals in 2023 and 10/25 individuals in 2024 for which sera were collected had AIV antibodies. Based on additional testing using hemagglutination inhibition, virus neutralization, and an enzyme-linked lectin assay, 94 and 100% (2023 and 2024, respectively) of the seropositive birds tested positive for antibodies to both H5 and N1, suggesting previous infection with HPAI H5N1. These results are consistent with survival and limited clinical effects related to HPAI H5N1 infections. Furthermore, these results suggest that population immunity to HPAI H5N1 within the Chesapeake Bay might reduce future infections and potential population impacts should HP H5N1 remain on the landscape, though immunity may be waning across time. Because results are based on a single population, additional testing for both infection and antibodies as well as continued monitoring could enhance understanding of antibody persistence.

Source: US National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/39911059/

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Emergence of a Novel #Reassortant Clade 2.3.2.1c Avian #Influenza A #H5N1 Virus Associated with #Human Cases in #Cambodia

Abstract

After nearly a decade without reported human A/H5N1 infections, Cambodia faced a sudden resurgence with 16 cases between February 2023 and August 2024, all caused by A/H5 clade 2.3.2.1c viruses. Fourteen cases involved a novel reassortant A/H5N1 virus with gene segments from both clade 2.3.2.1c and clade 2.3.4.4b viruses. The emergence of this novel genotype underscores the persistent and ongoing threat of avian influenza in Southeast Asia. This study details the timeline and genomic epidemiology of these infections and related poultry outbreaks in Cambodia.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2024.11.04.24313747v2

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

 One Cygnus species wild bird in Sachsen Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6245

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Viral #kinetics of #H5N1 #infections in dairy #cattle

Abstract

Since early-2024 unprecedented outbreaks of highly pathogenic avian influenza H5N1 clade 2.3.4.4b have been ongoing in dairy cattle in the United States with significant consequences for the dairy industry and public health. Estimation of key epidemiological parameters is required to support outbreak response, including predicting the likely effectiveness of interventions and testing strategies. Here we pool limited publicly available data from three studies of naturally and experimentally infected dairy cattle. We quantify Ct value trajectories of infected dairy cattle and the relationship between Ct value and the log-titre of infectious virus, a proxy for infectiousness. We estimate that following infection peak Ct values are rapidly reached within 1--2 days with a population mean Ct value of 16.9 (13.2, 20.5). We identify a critical threshold Ct value of 21.5 (20.1, 23.6), with values of Ct value above this threshold representing little-to-no infectious viral load. Finally, we estimate the distribution of the duration of infectiousness for dairy cattle (i.e. the duration their Ct value remains above the critical threshold) with a population median of 6.2 (2.8, 13.1) days.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.02.01.636082v1

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#USA, APHIS Confirms {Avian #Influenza #H5N1} #D11 #Genotype in Dairy #Cattle in #Nevada

On January 31, 2025, the USDA Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories (NVSL) confirmed by whole genome sequence the first detection of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b, genotype D1.1 in dairy cattle. 

This confirmation was a result of State tracing and investigation, following an initial detection on silo testing under the USDA’s National Milk Testing Strategy (NMTS) in Nevada. 

USDA APHIS continues to work with the Nevada Department of Agriculture by conducting additional on-farm investigation, testing, and gathering additional epidemiological information to better understand this detection and limit further disease spread. 

This is the first detection of this virus genotype in dairy cattle (all previous detections in dairy cattle have been HPAI H5N1 clade 2.3.4.4b, genotype B3.13). 

Genotype D1.1 represents the predominant genotype in the North American flyways this past fall and winter and has been identified in wild birds, mammals, and spillovers into domestic poultry. 

The detection does not change USDA’s HPAI eradication strategy and is a testament to the strength of our National Milk Testing Strategy (NTMS). In the interest of sharing information of import to the scientific community, APHIS will publish a technical brief on the findings on our website and post the sequence data on GenBank in the coming week. 

Source: Department of Agriculture, https://www.aphis.usda.gov/news/program-update/aphis-confirms-d11-genotype-dairy-cattle-nevada-0

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Differential #protection against #SARS-CoV-2 #reinfection pre- and post- #Omicron

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly evolved over short timescales, leading to the emergence of more transmissible variants such as Alpha and Delta. The arrival of the Omicron variant marked a major shift, introducing numerous extra mutations in the spike gene compared with earlier variants. These evolutionary changes have raised concerns regarding their potential impact on immune evasion, disease severity and the effectiveness of vaccines and treatments. In this epidemiological study, we identified two distinct patterns in the protective effect of natural infection against reinfection in the Omicron versus pre-Omicron eras. Before Omicron, natural infection provided strong and durable protection against reinfection, with minimal waning over time. However, during the Omicron era, protection was robust only for those recently infected, declining rapidly over time and diminishing within a year. These results demonstrate that SARS-CoV-2 immune protection is shaped by a dynamic interaction between host immunity and viral evolution, leading to contrasting reinfection patterns before and after Omicron’s first wave. This shift in patterns suggests a change in evolutionary pressures, with intrinsic transmissibility driving adaptation pre-Omicron and immune escape becoming dominant post-Omicron, underscoring the need for periodic vaccine updates to sustain immunity.

Source: Nature, https://www.nature.com/articles/s41586-024-08511-9

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

 A wild Barnacle Goose in Rogaland Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6244

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