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Washington state: 2022-2026 bird flu in wild birds

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  • #16
    Source: https://www.thedailyworld.com/news/b...harbor-county/

    Bird flu detected in Grays Harbor County
    Prolonged outbreak in wild birds could signal new course for virus, scientists say
    By Clayton Franke • December 3, 2022 1:30 am

    The evening of Nov. 9, just before dark, Vivian Dahlin drove her Jeep onto the beach at Chance a La Mer in Ocean Shores. As her tires pushed through the tire-tracked sand, she scanned the beach and noticed a gray lump lying motionless in the roadway. As she got closer, she realized it was a bird.

    “I drove up to it, and I sat and watched it,” said Dahlin, who regularly volunteers rescuing birds for the Washington Department of Fish and Wildlife. “I sort of talked to it. It didn’t move. I drove around it a couple of times, and it didn’t move. That’s not normal.”

    Despite its behavior, the bird was “quite alive,” Dahlin said. The bird — which to Dahlin looked like a small goose — sat upright, nodding its head off to one side. It didn’t flee when Dahlin nudged it with her dog-ball launcher.

    After scooping it into a carrier, Dahlin took the bird to the Twin Harbors Wildlife Center in Montesano, which sent test samples from the bird to a Washington State University wildlife disease lab in Pullman.

    The bird, a Cackling Goose, died soon after...

    Comment


    • #17
      Source: https://westseattleblog.com/2022/12/...ptoms-on-alki/

      WEST SEATTLE WILDLIFE: Swan with bird-flu symptoms on Alki
      December 3, 2022 2:25 pm
      | West Seattle beaches | West Seattle news | Wildlife

      2:25 PM: That’s Kersti Muul‘s photo of a Trumpeter Swan seen at Alki this morning, showing signs of Highly Pathogenic Avian Influenza, aka “bird flu.” She says it was last seen headed toward Duwamish Head, but wants to remind everyone to keep your distance – and especially to keep dogs leashed (they’re not supposed to be on the beach anyway), as this is a contagious disease for which there is no cure. It’s also a risk to other wild birds and has led to Bald Eagle deaths, as reported here recently. Here’s background on the current nationwide situation...

      Comment


      • #18
        Source: https://komonews.com/news/local/more...tcom-snohomish

        Suspected bird flu outbreak leads to deaths of 700 birds around Skagit Bay
        by KOMO News StaffThursday, December 8th 2022

        The Washington Department of Fish and Wildlife is warning of a suspected avian influenza outbreak among waterfowl after more than 700 birds, most of them juvenile snow geese, were recently found dead around Skagit Bay.

        WDFW said Thursday that samples have been taken from the birds for testing for avian influenza more commonly known as bird flu, with the H5N1 strain of highly pathogenic avian influenza suspected. While the strain is very contagious among birds, WDFW said it does not appear to easily infect humans...

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        • #19
          Source: https://www.yaktrinews.com/suspected...a-county-area/

          Suspected outbreak of bird flu in Walla Walla County area
          According to information from the health department, the Washington Department of Fish and Wildlife sent biologists to an area where a large number of sick or dead waterfowl were found.
          Posted: December 30, 2022 4:39 PM
          Updated: December 30, 2022 4:58 PM
          by Erin Wencl

          WALLA WALLA CO., Wash. – The Walla Walla County Department of Community Health confirmed Friday it is investigating a suspected outbreak of bird flu in the area.

          According to information from the health department, the Washington Department of Fish and Wildlife sent biologists to an area where a large number of sick or dead waterfowl were found.

          Samples were sent to the National Veterinary Services Laboratories to get a confirmation.

          Health officials from the state said they suspect the birds were infected with the H5N1 strain, which is highly contagious among the bird population...


          Comment


          • #20
            United States of America - Influenza A viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Follow up report 63

            GENERAL INFORMATION
            COUNTRY/TERRITORY OR ZONE
            ZONE

            ANIMAL TYPE
            TERRESTRIAL

            DISEASE CATEGORY
            OIE-listed

            EVENT ID
            4247

            DISEASE
            Influenza A viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-)

            CAUSAL AGENT
            Highly pathogenic avian influenza virus

            GENOTYPE / SEROTYPE / SUBTYPE
            H5N1

            START DATE
            2021/12/30

            REASON FOR NOTIFICATION
            Recurrence of an eradicated disease

            DATE OF LAST OCCURRENCE
            2017/03/27

            CONFIRMATION DATE
            2022/01/13

            EVENT STATUS
            On-going

            END DATE
            -

            SELF-DECLARATION
            NO

            REPORT INFORMATION
            REPORT NUMBER
            Follow-up report 63

            REPORT ID
            FUR_160686

            REPORT REFERENCE
            -

            REPORT DATE
            2023/05/04

            REPORT STATUS
            Validated

            NO EVOLUTION REPORT
            -

            EPIDEMIOLOGY
            SOURCE OF EVENT OR ORIGIN OF INFECTION
            migratory waterfowl

            EPIDEMIOLOGICAL COMMENTS
            Highly pathogenic avian influenza (HPAI) H5N1 Eurasian lineage goose/Guangdong clade 2.3.4.4b was confirmed in a wild barn owl (Tyto alba).
            The USDA Animal and Plant Health Inspection Service (APHIS), in conjunction with State Animal Health and Wildlife Officials, are conducting comprehensive epidemiological investigations and enhanced surveillance in response to the HPAI H5N1 related events in non-poultry species. Affected population counts are based on estimated inventories from the date the outbreak was first reported to WOAH. According to article 10.4.1.4 of the Terrestrial Animal Health Code, Member Country should not impose bans on the international trade of poultry commodities in response to notification of infection with any Influenza A viruses in birds other than poultry. For updated information about HPAI testing of wild birds in the United States, see: https://www.aphis.usda.gov/aphis/our...enza/2022-hpai.
            ...
            NEW OUTBREAKS

            OB_117911 - SKAGIT COUNTY
            OUTBREAK REFERENCE
            -

            START DATE
            2022/12/12

            END DATE
            2022/12/31

            DETAILED CHARACTERISATION
            -

            FIRST ADMINISTRATIVE DIVISION
            Washington

            SECOND ADMINISTRATIVE DIVISION
            Skagit

            THIRD ADMINISTRATIVE DIVISION
            -

            EPIDEMIOLOGICAL UNIT
            Not applicable

            LOCATION
            Skagit County

            Latitude, Longitude
            48.418 , -122.337

            (Approximate location)
            OUTBREAKS IN CLUSTER
            -

            MEASURING UNIT
            Animal

            AFFECTED POPULATION DESCRIPTION
            Wild barn owl (Tyto alba). Bird was found dead.

            SpeciesSusceptibleCasesDeathsKilled and Disposed ofSlaughtered/ Killed for commercial useVaccinated
            Barn Owl (Common Barn-Owl) (WILD)
            Wild

            NEW------
            TOTAL------
            ...

            Comment


            • #21
              Bird flu outbreak stokes fears for Washington’s wild birds

              New strain of avian flu has killed dozens of birds on a small Puget Sound island. Cases have turned up elsewhere as well.

              BY: LAUREL DEMKOVICH - AUGUST 15, 2023 2:40 PM


              snip

              Since July 1, the Department of Fish and Wildlife has collected more than 1,224 dead Caspian tern carcasses – most of which are adults – and more than 158 dead gull carcasses – most of which are chicks.

              The long-term impacts of the Rat Island outbreak are “unknown,” Haman said. “I think time will tell.”


              more... https://idahocapitalsun.com/2023/08/...ns-wild-birds/

              Comment


              • #22
                Source: https://www.seattletimes.com/seattle...birds-removed/

                WA officials warn of bird flu outbreak in state park; more than 1,700 dead birds removed
                Sep. 1, 2023 at 9:41 pm
                By Daisy Zavala Magaña
                Seattle Times staff reporter

                People should avoid contact with wild animals, given a deadly outbreak of avian influenza, known as bird flu, first noted in early July among birds and seals near Fort Flagler State Park in Jefferson County, health officials advised Friday evening.

                Washington Department of Fish and Wildlife staff have removed over 1,700 dead Caspian terns and gulls on Rat Island, a wildlife preserve, and adjacent shores, according to the Washington State Department of Health. Officials have closed Rat Island due to the outbreak.

                While preliminary tests indicate three harbor seals were also infected, final results are pending. Officials found Caspian terns infected with the bird flu along the lower Columbia River, the Port of Everett and Port of Tacoma, the health agency said.​..

                Comment


                • #23
                  Source: https://www.kiro7.com/news/local/dep...O5YORNIHOK6ZM/

                  Department of Fish and Wildlife warns public of Lake Tye bird flu outbreak
                  By KIRO 7 News Staff
                  November 10, 2023 at 3:47 pm PST​


                  MONROE, Wash. — Washington Department of Fish and Wildlife is warning the public of Cackling Geese that have been exposed to the bird flu at Lake Tye.

                  Officials say that they are continuing to monitor the situation while removing both sick and dead geese from the park.

                  On Nov. 5, the City of Monroe got reports from the WDFW that several Cackling Geese that had landed at Lake Tye Park were showing symptoms of bird flu.

                  The park has not been closed but WDFW is posting signs to inform the public...


                  Comment


                  • #24
                    Source: https://www.heraldnet.com/news/over-...n-monroe-park/


                    Over 70 geese have died of suspected bird flu in Monroe park
                    State officials said outbreaks of this size are common in fall. People can help by not feeding birds at Lake Tye.
                    by Ta'Leah Van Sistine
                    Wednesday, November 15, 2023 4:24pm


                    MONROE — An estimated 70 to 80 cackling geese have died since early November from suspected bird flu at Lake Tye Park, state officials said.

                    On Nov. 4, the state Department of Fish and Wildlife began receiving reports of infected cackling geese at the Monroe park. The city posted signs at the park about the infections, but hadn’t issued any closures as of this week.​...

                    Comment


                    • #25
                      Detections of Highly Pathogenic Avian Influenza in Wild Birds
                      ...
                      State County Collection Date Date Detected HPAI Strain Bird Species WOAH Classification Sampling Method


                      Washington Whitman 11/22/2023 8/30/2024 EA/AM H5N1 Great horned owl Wild bird Morbidity/Mortality
                      Washington Grays Harbor 10/23/2023 6/5/2024 EA H5N1 Bald eagle Wild bird Morbidity/Mortality
                      Washington Spokane 3/11/2024 3/20/2024 EA/AM H5N1 Bald eagle Wild bird Morbidity/Mortality
                      Washington Kitsap 12/12/2023 3/1/2024 EA H5N1 Western sandpiper Wild bird Morbidity/Mortality
                      Washington Clark 2/2/2023 2/29/2024 EA H5N1 Bald eagle Wild bird Morbidity/Mortality
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/29/2024 2/13/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Clark 1/27/2024 2/12/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/27/2024 2/12/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/27/2024 2/12/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/27/2024 2/12/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/27/2024 2/12/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/25/2024 2/9/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/25/2024 2/9/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/25/2024 2/9/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/25/2024 2/9/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/25/2024 2/9/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/25/2024 2/9/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Grant 1/28/2024 2/9/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Benton 1/24/2024 2/6/2024 EA H5N1 Bald eagle Wild bird Morbidity/Mortality
                      Washington Clark 1/23/2024 2/6/2024 EA H5 Mallard Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Mallard Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Green-winged teal Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern pintail Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest
                      Washington Clark 1/23/2024 2/6/2024 EA H5N1 Northern shoveler Wild bird Hunter harvest

                      ...

                      View the latest information on detections of highly pathogenic avian influenza (HPAI) in wild birds.

                      Comment


                      • #26
                        Detections of Highly Pathogenic Avian Influenza in Wild Birds

                        Last Modified: September 10, 2024
                        ...
                        State County Collection Date Date Detected HPAI Strain Bird Species WOAH Classification Sampling Method

                        Washington Clallam 11/14/2023 9/4/2024 EA H5N1 Peregrine falcon Wild bird Morbidity/Mortality

                        ...

                        https://www.aphis.usda.gov/livestock...ons/wild-birds

                        Comment


                        • #27
                          Detections of Highly Pathogenic Avian Influenza in Wild Birds

                          Last Modified: November 12, 2024
                          ...
                          State County Collection Date Date Detected HPAI Strain Bird Species WOAH Classification Sampling Method

                          Washington Snohomish 10/11/2024 11/6/2024 EA H5 Cackling goose Wild bird Morbidity/Mortality
                          Washington Skagit 10/10/2024 11/6/2024 EA H5 Great horned owl Wild bird Morbidity/Mortality
                          Washington Grant 10/13/2024 11/4/2024 EA H5N1 American wigeon Wild bird Hunter harvest
                          Washington Grant 10/13/2024 11/4/2024 EA H5 Northern shoveler Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA H5 Green-winged teal Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA H5 Green-winged teal Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA H5 Green-winged teal Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA H5 Green-winged teal Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA H5 Mallard Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA/AM H5N1 American wigeon Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA H5 Northern pintail Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA/AM H5N1 Northern pintail Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA H5 Northern shoveler Wild bird Hunter harvest
                          Washington Grant 10/15/2024 11/4/2024 EA/AM H5N1 Northern shoveler Wild bird Hunter harvest
                          ...


                          Comment


                          • #28
                            Source: https://www.king5.com/article/life/a...e-09d9b18329b3

                            Woodland Park Zoo reports first suspected case of avian influenza
                            The infected goose, part of a rare and threatened species, was found deceased in an off-exhibit area of the zoo earlier this week.
                            Author: Adel Toay
                            Published: 12:35 PM PST November 15, 2024
                            Updated: 12:35 PM PST November 15, 2024


                            SEATTLE — The Woodland Park Zoo has confirmed the first suspected case of Highly Pathogenic Avian Influenza (HPAI) following the death of a red-breasted goose earlier this week.

                            Preliminary test results from Thursday indicated the presence of the virus.

                            The goose, part of a rare and threatened species, was found deceased in an off-exhibit area, according to the zoo. The zoo had already enacted several precautionary measures earlier this year due to rising HPAI cases in the region, including draining open-air bird pools and moving free-roaming peacocks indoors.

                            In response to the confirmed case, the zoo said it is intensifying its biosecurity measures including canceling all bird-related guest experiences, including volunteer activities, private tours and penguin feeding. The walk-through aviaries will remain closed to the public. The Tropical Rainforest exhibit will stay open...


                            Comment


                            • #29
                              Bird flu decimated tern colony in northwest Washington

                              Study findings provide new details on a Caspian tern die-off near Port Townsend in 2023 and how the virus killed seals in the region, infecting their brains.


                              By: Bill Lucia - November 18, 2024 4:00 am

                              More than half a colony of Caspian terns on a small island near Port Townsend died last year amid an outbreak of bird flu, underscoring the harsh effects the disease can have on wildlife.

                              Researchers say they directly counted 1,101 dead adult terns and 520 dead chicks and that at least 53-56% of the adult birds in a colony on Rat Island, in northern Puget Sound, were wiped out. After factoring in Caspian tern deaths in other parts of the region, the researchers estimated about 10-14% of the birds in the Pacific flyway were lost last year to bird flu.

                              The researchers also studied harbor seals that died from the virus on or around Rat Island during the same timeframe and found that the disease had attacked the animals differently than it did birds, causing severe inflammation in their brains.
                              ...


                              ------------------------------

                              ORIGINAL RESEARCH article
                              Front. Vet. Sci., 31 October 2024
                              Sec. Zoological Medicine
                              Volume 11 - 2024 | https://doi.org/10.3389/fvets.2024.1483922

                              This article is part of the Research Topic
                              Insights in Zoological Medicine: 2023
                              View all 9 articles

                              A comprehensive epidemiological approach documenting an outbreak of H5N1 highly pathogenic avian influenza virus clade 2.3.4.4b among gulls, terns, and harbor seals in the Northeastern Pacific

                              Katherine H. Haman
                              Katherine H. Haman1*Scott F. PearsonScott F. Pearson1Justin BrownJustin Brown2Lauren A. FrisbieLauren A. Frisbie3Sara PenhallegonSara Penhallegon4Azeza M. FalghoushAzeza M. Falghoush5Rebecca M. WolkingRebecca M. Wolking5Brandi K. TorrevillasBrandi K. Torrevillas5Kyle R. Taylor,Kyle R. Taylor5,6Kevin R. Snekvik,Kevin R. Snekvik5,6Sarah A. TanedoSarah A. Tanedo1Ilai N. KerenIlai N. Keren1Elizabeth A. AshleyElizabeth A. Ashley7Casey T. ClarkCasey T. Clark1Dyanna M. LambournDyanna M. Lambourn1Chrissy D. Eckstrand,Chrissy D. Eckstrand5,6Steven E. Edmonds,Steven E. Edmonds5,6Emma R. Rovani-Rhoades,Emma R. Rovani-Rhoades5,6Hanna OlteanHanna Oltean3Kristin WilkinsonKristin Wilkinson8Deborah FauquierDeborah Fauquier9Allison BlackAllison Black3Thomas B. Waltzek,Thomas B. Waltzek5,6
                              1Wildlife Program, Science Division, Washington Department of Fish and Wildlife, Olympia, WA, United States
                              2Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, United States
                              3Washington State Department of Health, Shoreline, WA, United States
                              4Center Valley Animal Rescue, Quilcene, WA, United States
                              5Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States
                              6Department of Veterinary Microbiology and Pathology, Washington State University College of Veterinary Medicine, Pullman, WA, United States
                              7EpiCenter for Disease Dynamics, One Health Institute, School of Veterinary Medicine, University of California Davis, Davis, CA, United States
                              8West Coast Regional Office, National Marine Fisheries Service, Seattle, WA, United States
                              9Office of Protected Resources, National Marine Fisheries Service, Silver Spring, MD, United States


                              Highly pathogenic avian influenza viruses (HPAIV) H5N1 clade 2.3.4.4b continue to have unprecedented global impacts on wild birds and mammals, with especially significant mortality observed in colonial surface-nesting seabirds and in some marine mammal species. In July of 2023 H5N1 HPAIV 2.3.4.4b was detected in Caspian terns nesting on Rat Island, Washington USA. An estimated 1,800–1,900 adult terns populated the breeding colony, based on aerial photographs taken at the start of the outbreak. On a near-weekly basis throughout July and August, we counted and removed carcasses, euthanized moribund birds, and collected swab and tissue samples for diagnostic testing and next-generation sequencing. We directly counted 1,101 dead Caspian tern adults and 520 dead chicks, indicating a minimum 56% loss of the adult colony population and potential impacts to reproductive success. Combining the observed mortality on Rat Island with HPAI-related Caspian tern deaths recorded elsewhere in Washington and Oregon, we estimate that 10–14% of the Pacific Flyway population was lost in the summer of 2023. Comparatively few adult Glaucous-winged gulls (hybrids) nesting on Rat Island died (~3% of the local population), although gull chick mortality was high. Sixteen harbor seals in the immediate or nearby area stranded during the outbreak, and H5N1 HPAIV was detected in brain and/or lung tissue of five seals. These cases are the first known detections of HPAIV in a marine mammal on the Pacific coast of North America. Phylogenetic analyses support the occurrence of at least three independent avian-mammalian virus spillover events (tern or gull to harbor seal). Whole genome sequencing indicated that H5N1 HPAIV may have been introduced to Washington from Caspian terns in Oregon. Ongoing monitoring and surveillance for H5N1 HPAIV in the marine environment is necessary to understand the epidemiology of this virus, assess conservation impacts to susceptible species, and provide support for data-driven management and response actions.
                              ...
                              5 Conclusion
                              The global impact of H5N1 HPAIV clade 2.3.4.4b on wild birds and mammals is considerable based on raw mortality counts. However, few studies have accurately assessed the actual mortality and pattern of mortality across an entire outbreak or combined disease surveillance data with population monitoring (prior to the outbreak) to assess local colony and population impacts. Our investigation of the Rat Island outbreak employed comprehensive and multifaceted approaches that are uncommon in published studies of HPAI in free-ranging wildlife. In addition to the mortality event investigation, we also conducted population monitoring of Caspian terns at the onset of the outbreak, which allowed us to estimate total mortality. Using raw carcass counts collected nearly weekly during the outbreak, we were able to calculate population impacts of this outbreak on the terns. This was combined with diagnostic and genomic data confirming H5N1 HPAIV clade 2.3.4.4b infections in several hosts, including the first documentation of HPAI in a marine mammal in the Northeast Pacific. We document clear host susceptibility differences between breeding adult Caspian terns and gulls nesting at the same colony and in close proximity, with significant population level impacts for Caspian terns in the Pacific Flyway, yet very little impact to adult gulls. Finally, we found consistent patterns of the timing of H5N1 detection, the pattern of virus mutation, and the pattern of bird movement.

                              As comprehensive as our data are, we still lack a full understanding of these species’ immunological response(s) to IAV infections, especially H5N1 HPAIV, and how this affects susceptibility and disease outcomes in face of acute HPAI outbreaks and ongoing circulation of IAVs in the environment. This information gap and our findings highlight the importance of combining population monitoring, traditional and molecular epidemiological tools, and serologic surveillance for investigating wildlife morbidity and mortality events to better understand their impacts. We recommend expanding our wildlife health approach beyond mortality surveillance efforts (i.e., counting the dead) to also focus on population-level impacts and how environmental, behavioral, and immunological differences influence host susceptibility to disease, especially as H5N1 HPAI continues to devastate wildlife around the globe.​
                              ...

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                              • #30
                                Detections of Highly Pathogenic Avian Influenza in Wild Birds

                                Last Modified: November 19, 2024
                                ...
                                Click image for larger version  Name:	image.png Views:	1 Size:	63.1 KB ID:	1000781
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