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Florida - Avian influenza detected in a bottlenose dolphin recovered in March 2022

Pathfinder

Editor, Senior Moderator
A first: Avian influenza detected in American dolphin


Published: Sep 7, 2022 By: Sarah CareyCategory: University of Florida, UF Health, College of Veterinary Medicine



The detection of highly pathogenic avian influenza virus in a bottlenose dolphin recovered by University of Florida marine animal rescuers marks the first time the virus has been identified in a cetacean in America. (Photo courtesy of the Florida Fish and Wildlife Conservation Commission)


A bottlenose dolphin found dead in Florida’s Dixie County was infected with the highly pathogenic avian influenza virus, or HPAIV, making it the first cetacean to be found with the virus in America and only the second known case in the world.

The young male dolphin was recovered in March at Horseshoe Beach by the University of Florida’s marine animal rescue team. A collaboration between UF College of Veterinary Medicine researchers and state and federal laboratories identified the unexpected infection with HPAIV, commonly known as bird flu. The virus recovered from the dolphin belonged to clade 2.3.4.4b of the Eurasian H5 viral lineage.

Wild birds have spread H5 clade 2.3.4.4b HPAIV widely in North America and Europe this year. The virus primarily affects wild birds and domesticated poultry but only rarely infects people. Researchers suspect the dolphin likely got infected by interacting with a wild bird killed by HPAIV.

“While obviously the presence of HPAIV is a concern, the key takeaway for us is that additional caution should be taken by those handling or encountering wild dolphins during rescue events or while performing necropsies,” said Mike Walsh, D.V.M., a clinical associate professor with UF’s College of Veterinary Medicine who leads the animal rescue team and performed the dolphin’s necropsy with others.

There has been only one report of H5 clade 2.3.4.4b in people in 2022.

Richard Webby, Ph.D., directs the World Health Organization Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds at St. Jude Children’s Research Hospital. The WHO Center at St. Jude, which analyzes animal flu viruses and their potential risk to human health, will analyze the dolphin tissue samples supplied by the UF team.

“The virus has some features that make further study and follow-up on mammalian cases important, but the virus does not currently contain the features we know are required for transmission between humans and likely other mammalian hosts,” Webby said. “In addition, the recent discovery of HPAIV in a porpoise in Sweden almost certainly suggests that the Florida dolphin finding isn’t a one-off, unique event.”

The UF team did not immediately suspect anything out of the ordinary when they performed a routine necropsy. Tests for common causes of deaths in dolphins turned up negative.

“However, this dolphin had inflammation of the brain and also the tissues surrounding the brain, known as the meninges,” said Robert Ossiboff, D.V.M., Ph.D., an associate professor of veterinary anatomical pathology at UF. “This finding was unusual.”

Andrew Allison, Ph.D., an assistant professor of veterinary virology at UF, studies viruses that normally circulate in wildlife populations, primarily wild birds and mammals. He knew that HPAIV was a rapidly growing concern for wild bird populations in Florida.

“Although avian flu infection had never been documented in a dolphin, the high incidence of the virus in wild birds within the state in the spring — specifically aquatic bird species such as ducks, gulls, terns and herons — suggested that encounters between dolphins and dying or dead birds near the shoreline was not out of the realm of possibility,” he said.

Wild birds that succumb to HPAIV often have neurologic signs with virus found in their brains. Since the dolphin had inflammation of the brain and meninges that could have been caused by a virus, Allison believed that the dolphin could have died from HPAIV infection.

On the basis of these initial suspicions, the UF researchers sent brain and lung samples of the dolphin to the state’s Bronson Animal Disease Diagnostic Laboratory in Kissimmee, a nationally accredited facility and a member of the National Animal Health Laboratory network, or NAHLN. This lab is approved for and routinely performs testing for animal pathogens of significant consequence that can pose severe threats to animals and humans. There, suspicions were confirmed, as the samples tested positive for avian flu. As a NAHLN laboratory, avian flu detections are sent on to the National Veterinary Diagnostic Laboratory in Ames, Iowa, for characterization by genetic sequencing to identify the specific strain of avian flu.

UF’s marine animal rescue team is a member of the National Oceanic and Atmospheric Administration Southeast Regional Stranding Network, which authorizes members to assist and investigate stranded marine mammals. The UF rescue team works closely with the stranding network, especially when investigating pathogens with unknown effects in cetaceans.

https://ufhealth.org/news/2022/first...erican-dolphin





See also:
Sweden: H5N1 in a porpoise
https://flutrackers.com/forum/forum/europe/h5n1-tracking/sweden/957776-sweden-h5n1-in-a-porpoise
 
For a wild animal dead from unknown causes, think that is actually pretty good.
The necropsy team deserves plaudits, finding brain inflammation in a rather dead dolphin can't be an easy job.
Also a sobering reminder that viruses such as for flu and Covid are happily mutating in the wildlife they infect, so stuff can come out of left field quite unexpectedly.
 
Article
Open access

Published: 18 April 2024

Highly pathogenic avian influenza A(H5N1) virus in a common bottlenose dolphin (Tursiops truncatus) in Florida

Allison Murawski, Thomas Fabrizio, Robert Ossiboff, Christina Kackos, Trushar Jeevan, Jeremy C. Jones, Ahmed Kandeil, David Walker, Jasmine C. M. Turner, Christopher Patton, Elena A. Govorkova, Helena Hauck, Suzanna Mickey, Brittany Barbeau, Y. Reddy Bommineni, Mia Torchetti, Kristina Lantz, Lisa Kercher, Andrew B. Allison, Peter Vogel, Michael Walsh & Richard J. Webby
Communications Biology volume 7, Article number: 476 (2024) Cite this article


Abstract

Since late 2021, highly pathogenic avian influenza (HPAI) viruses of A/goose/Guangdong/1/1996 (H5N1) lineage have caused widespread mortality in wild birds and poultry in the United States. Concomitant with the spread of HPAI viruses in birds are increasing numbers of mammalian infections, including wild and captive mesocarnivores and carnivores with central nervous system involvement. Here we report HPAI, A(H5N1) of clade 2.3.4.4b, in a common bottlenose dolphin (Tursiops truncatus) from Florida, United States. Pathological findings include neuronal necrosis and inflammation of the brain and meninges, and quantitative real time RT-PCR reveal the brain carried the highest viral load. Virus isolated from the brain contains a S246N neuraminidase substitution which leads to reduced inhibition by neuraminidase inhibitor oseltamivir. The increased prevalence of A(H5N1) viruses in atypical avian hosts and its cross-species transmission into mammalian species highlights the public health importance of continued disease surveillance and biosecurity protocols.

Introduction

There has been an explosive expansion in the geographic distribution and prevalence of highly pathogenic avian influenza (HPAI) A(H5N1) of hemagglutinin (HA) clade 2.3.4.4b viruses in animal populations in the Americas since 20211,2,3. These viruses have raised concern due to their significant adverse economic impacts on the poultry industry and widespread mortality in wild bird species1. Notably, the virus has also been detected in a number of raptors such as eagles, owls, and vultures, suggesting predation and scavenging of infected birds are efficient means of HPAI virus transmission1,2,4.

Recently, clade 2.3.4.4b A(H5N1) viruses have been responsible for mortalities in sea lions (Otaria flavescents) in Peru and Chile, along with harbor (Phoca vitulina) and gray (Halichoerus grypus) seals in New England and Canada5,6,7. Historically, multiple unusual mortality events in seal populations have been associated with avian influenza. Harbor seals (Phoca vitulina) appear to be the most susceptible marine mammal species for developing fatal respiratory disease, although the reason for this is currently unknown8,9. Many of these previous seal influenza-related mortality events that occurred in New England seal populations were caused by different influenza subtypes including A(H7N7) in 1979, A(H4N5) in 1983, A(H4N6) in 1991, A(H3N3) in 1992, and A(H3N8) in 201110,11,12,13,14. Other significant outbreaks in seals have occurred in European waters (including A(H10N7) in 2014)8,15,16,17.

In contrast to pinniped species, avian influenza viruses have rarely been detected in cetaceans and have not been associated with any unusual mortality events. Avian influenza viruses have been isolated from cetaceans including baleen whales (family Balaenopteridae)13,18 such as the common minke whale (Balaenoptera acutorostrata)19, as well as pilot whales (Globicephala melaena)13,20,21, Dall’s porpoise (Phocoenoides dalli)19, and belugas (Delphinapterus leucas)13,22.

The recent spread of clade 2.3.4.4b A(H5N1) viruses has been accompanied by novel infections of cetacean species around the world including three common dolphins (Delphinus delphis) in Peru, Wales, and England, two harbor porpoises (Phocoena phocoena) in Sweden and England, and an Atlantic white-sided dolphin (Lagenorhynchus acutus) in Canada6,23. In the harbor porpoise from Sweden, influenza virus was predominately found within the brain causing meningoencephalitis, consistent with this current report and other recent detections in terrestrial mammals23. The harbor porpoise displayed neurological signs including circling, inability to right itself, and subsequent drowning23.

Similarly, spillover of clade 2.3.4.4b A(H5N1) in terrestrial mammals has also shown viral infection predominately in the brain, along with associated neurological signs. In 2006, a stone marten (Martes foina) naturally infected with a HPAI A(H5N1) virus developed neurological symptoms due to encephalitis, likely secondary to consumption of an infected wild waterfowl24. Other wild carnivore species have been diagnosed with HPAI A(H5N1), including a study of wild terrestrial mammals in the United States showing that 53 of 57 HPAI A(H5N1) virus-infected animals displayed neurological abnormalities25.

Here we report an infection of HPAI A(H5N1) clade 2.3.4.4b in a common bottlenose dolphin (Tursiops truncatus) in Florida, United States, with the highest viral load in the brain causing meningoencephalitis. Adding to the existing literature on A(H5N1) viruses in cetacean species, the availability of tissues and multiple samples from this animal allowed us to combine a pathologic and virologic evaluation of the infection. Research was conducted to confirm the presence of A(H5N1) virus in dolphin tissues, biologically characterize the virus, and to determine the phylogenetic relationship between viruses from the dolphin and local wild bird populations. This study highlights the importance of combining histological lesions with virus isolation in order to better understand HPAI A(H5N1).

Results

Stranding response


On 29 March 2022, the Florida Fish and Wildlife Conservation Commission’s Marine Mammal Pathobiology Laboratory (FWC MMPL) notified the University of Florida Marine Animal Rescue Program (UF MAR) of a dolphin in distress in a canal north of 178 4th Ave. West Horseshoe Beach in Dixie County, FL 32648 (29.44222°N, -83.29004°W). The complainant stated that the live dolphin was located between a seawall and dock piling, measuring approximately 20 centimeters wide, in the canal behind their home. The complainant attempted to free the dolphin while providing supportive care, however, the dolphin passed shortly after discovery and prior to the arrival of UF MAR. The dolphin was packed in ice and transported to the University of Florida College of Veterinary Medicine (UF CVM) on 29 March 2022 to be stored in a cooler for necropsy the following day.
...​

https://www.nature.com/articles/s42003-024-06173-x​
 
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