Weekly Vet Report: A first for canine noise aversion and separation anxiety, an RNA veterinary vaccine moves closer to EU authorization, & more

A look at three recent developments in animal health.

FDA approves first drug indicated for both noise aversion and separation anxiety in dogs

The FDA has approved tasipimidine oral solution (Tessie; Orion Corporation) for the treatment of noise aversion and separation anxiety in dogs. It’s the first product to receive federal clearance for both conditions in a single indication.¹

Although medications have previously been approved for each condition separately, tasipimidine is the first to carry dual labeling. The drug is an α-2 adrenoceptor agonist that works by reducing heightened sympathetic nervous system activity associated with fear and anxiety. It’s administered orally approximately 1 hour before a predictable noise event or anticipated owner departure, and may be given up to 3 times in a 24-hour period with at least 3 hours between doses.

Effectiveness was supported by controlled clinical field studies including a study of 160 dogs for noise aversion and an 8-week study of 224 dogs for separation anxiety. The most commonly reported adverse reactions included vomiting and lethargy across both indications, with diarrhea also reported in the separation anxiety study.

The dual indication may be particularly relevant for dogs undergoing behavioral modification for both conditions simultaneously. Christopher Pachel, DVM, DACVB, CABC, owner and lead clinician at Animal Behavior Clinic in Portland, Oregon, told dvm360 that concurrent noise aversion and separation anxiety are not uncommon in dogs, and that having a medication covering both may help reduce the risk of setbacks during training, such as when a dog making progress is unexpectedly left alone during a noise event.² Full interview available here.

Europe moves toward first RNA veterinary vaccine authorization

The European Medicines Agency (EMA) has recommended marketing authorization for Nobivac NXT HCPChFeLV, a cat vaccine that would become the first veterinary vaccine authorized in the European Union to contain self-amplifying RNA as an active substance.³

The vaccine targets five pathogens: feline herpesvirus type 1, feline calicivirus, feline panleukopenia virus, feline leukemia virus, and Chlamydia felis. For the first four pathogens and Chlamydia felis, the vaccine uses live attenuated strains. For feline leukemia virus specifically, it uses self-amplifying RNA packaged in a replication-deficient viral replicon particle, which delivers RNA to cells to trigger an immune response.³

The EMA's veterinary medicines committee reviewed data from 15 studies in closed animal facilities and one field study in 142 cats.³ The data showed adequate immune responses against all five pathogens, with immunity beginning approximately one week after vaccination. Duration of immunity is 3 years for feline panleukopenia virus and 1 year for the remaining pathogens. The most commonly reported adverse effects were injection site swelling and elevated temperature, both typically resolving within a day.³

The recommendation is going to the European Commission for a final legally binding decision.

Study finds H5N1 in cows' breath, grazing fields, and manure lagoons on California dairy farms

A study published in PLOS Biology has identified highly pathogenic avian influenza (H5N1) in parts of dairy farm environments not previously well characterized, raising questions about the full scope of transmission routes on affected operations.

Researchers from Emory University sampled air, wastewater, and milk on 14 H5N1-positive dairy farms across two California regions in 2024 and 2025.^4,5 They detected viral RNA in the exhaled breath of cows, in fields where cattle graze, and in manure lagoons. These areas also serve as stopping points for migratory birds.⁵ The virus was confirmed in milking parlor air on multiple farms and at two points in farm wastewater streams.⁵

In a longitudinal analysis of milk from individual mammary quarters of cows on one farm, researchers found a heterogeneous distribution of H5N1 positivity, meaning different quarters were affected in different animals, with no single quarter consistently positive across the herd. The authors note this pattern is inconsistent with contaminated milking equipment serving as the sole mode of transmission, as shared equipment would be expected to produce more uniform infection patterns.⁵

The study also found H5N1 antibodies in the milk of cows that showed no clinical signs during their farm's outbreak, suggesting subclinical infections may be more prevalent than current surveillance detects. On one farm, 6 of 10 cows with no observed drop in milk production tested positive for H5-specific antibodies.⁵

Sequence analysis of air and wastewater samples from one farm identified a viral variant with a mutation associated with improved binding to human cell receptors, though whether this specific mutation meaningfully alters human susceptibility has not been determined.

"Together, these results highlight the extensive environmental contamination of H5N1 on affected dairy farms and identify additional sources of viral exposure for cows, peridomestic wildlife, and humans," the authors of the study wrote.⁵ The study was led by researchers at Emory University's Center for Transmission of Airborne Pathogens.

References

1. Bautista-Alejandre A. FDA approves first drug for both noise aversion and separation anxiety in dogs. dvm360. May 6, 2026. Accessed May 8, 2026. https://www.dvm360.com/view/fda-approves-first-drug-for-both-noise-aversion-and-separation-anxiety-in-dogs
2. Coppock KC. Treating noise aversion and separation anxiety together. dvm360. May 7, 2026. Accessed May 8, 2026. https://www.dvm360.com/view/treating-noise-aversion-and-separation-anxiety-together
3. EMA recommends authorisation of first veterinary vaccine using RNA technology. News release. European Medicines Agency. April 17, 2026. Accessed May 8, 2026. https://www.ema.europa.eu/en/news/ema-recommends-authorisation-first-veterinary-vaccine-using-rna-technology
4. Beusekom MV. Sampling reveals possible novel sources of H5N1 avian flu transmission on dairy farms. University of Minnesota. May 5, 2026. Accessed May 8, 2026. https://www.cidrap.umn.edu/avian-influenza-bird-flu/sampling-reveals-possible-novel-sources-h5n1-avian-flu-transmission-dairy
5. Campbell AJ, Shephard M, Paulos AP, et al. Surveillance on California dairy farms reveals multiple possible sources of H5N1 influenza virus transmission. PLoS Biol. 2026;24(5):e3003761. doi:10.1371/journal.pbio.3003761