#SARS-CoV-2 within-host population expansion, diversification and #adaptation in #zoo #tigers, #lions and #hyenas

 

Abstract

SARS-CoV-2 rapidly adapts to new hosts following cross-species transmission; this is highly relevant as unique within-host variants have emerged following infection of susceptible wild and domestic animal species. Furthermore, SARS-CoV-2 transmission from animals (e.g., white-tailed deer, mink, domestic cats, and others) back to humans has been observed, documenting the potential of animal-derived variants to infect humans. Here, we investigate SARS-CoV-2 evolution and host-specific adaptation during an outbreak in Amur tigers (Panthera tigris altaica), African lions (Panthera leo), and spotted hyenas (Crocuta crocuta) at Denver Zoo in 2021. SARS-CoV-2 genomes from longitudinal samples from 16 individuals are evaluated for within-host variation and genomic signatures of selection, and we determine that the outbreak was likely initiated by a single spillover of a rare Delta sublineage. Within-host virus populations rapidly expand and diversify, and we detect signatures of purifying and positive selection, including strong positive selection in hyenas and in the nucleocapsid (N) gene in all animals. Four candidate species-specific adaptive mutations are identified: N A254V in lions and hyenas, and ORF1a E1724D, spike T274I, and N P326L in hyenas. These results reveal accelerated SARS-CoV-2 adaptation following host shifts in three non-domestic species in daily contact with humans.

Source: 

Link: https://www.nature.com/articles/s41467-025-66402-7

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

 

{By Charles J. Sharp - Own work, from Sharp Photography, sharpphotography.co.uk, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116380120}

Nineteen captive Painted Storks in the National Zoological Park, Delhi.

Source: WOAH, https://wahis.woah.org/#/in-review/6803

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Immunization with a novel #RNA replicon #vaccine confers long-lasting #protection against #H5N1 avian #influenza virus in 24 #bird species

Abstract

Highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 (clade 2.3.4.4b) have spread worldwide and caused the death of hundreds of millions of wild birds and domestic poultry. Moreover, spill over of H5N1 HPAIV from infected birds to more than 50 different mammalian species including humans has been recorded. While, licensed vaccines for protection of avian or mammalian species are not yet available, a few candidate vaccines are being trialled. Here, we report on the experimental vaccination of chickens and captive wild birds using a propagation-defective vesicular stomatitis virus (VSV), in which the essential envelope glycoprotein (G) protein gene was replaced by a modified hemagglutinin gene derived from a clade 2.3.4.4b H5N1 isolated in 2022 in the animal park of Bern, Switzerland. VSV∆G(H5mb) was produced on helper cells providing the VSV G protein in trans. Specific pathogen-free (SPF) chickens that were immunized twice via the intramuscular route with adjuvant-free VSV∆G(H5mb) replicon particles induced high levels of virus-neutralizing serum antibodies and were fully protected against lethal infection by H5N1 HPAIV (clade 2.3.4.4b). Notably, immunized animals did not shed challenge virus from the respiratory or gastrointestinal tract, suggesting that herd immunity can be achieved. The same vaccine was used to immunize a total of 317 captive wild birds at Bern Animal Park and Zoo Basel, representing 24 different species. No vaccine-associated side effects were observed. Birds without previous contact to H5Nx viruses produced high to very high H5-specific neutralizing antibody titers following the second immunization, while birds showing H5-specific antibodies prior to vaccination, already developed high neutralizing antibody titers after a single immunization. One year after vaccination, most animals still showed significant neutralizing antibody titers, indicating that VSV∆G(H5mb) is able to induce a long-lasting protective immune response. Our results indicate that VSV∆G(H5mb) is an extraordinary safe and highly efficacious vaccine to stop H5N1 replication in various avian species.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.01.15.633174v1

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