Study finds baloxavir most effective antiviral against avian flu in cats, questions oseltamivir efficacy
A bioRxiv preprint evaluated multiple antiviral drugs against highly pathogenic avian influenza (HPAI) H5N1 in feline cell cultures, finding baloxavir most effective while oseltamivir showed minimal efficacy. The study is significant because H5N1 infections in cats have an approximately 80% mortality rate, yet no antivirals have been tested in experimental feline models. The findings could inform veterinary treatment decisions for HPAI-infected cats and related species.
Researchers tested six antiviral compounds against HPAI clade 2.3.4.4.b virus in feline cell cultures (glial astrocytes and kidney cells). Baloxavir, a cap-dependent endonuclease inhibitor, demonstrated the strongest antiviral activity with EC50 values of 30 nM in astrocyte cells and 1 μM in kidney cells. Oseltamivir carboxylate, commonly used for influenza treatment, did not effectively inhibit viral replication in either cell line, contradicting anecdotal clinical evidence suggesting it may help infected cats. Other tested compounds—amantadine, rimantadine, GS-441524, and mutagenic NHC analogs—either failed to inhibit replication or showed significant cytotoxicity. The researchers recommend baloxavir as the first-line antiviral for veterinary treatment of HPAI-infected felines and related species, though they note this is in vitro data requiring further validation.
What's missing
The study is a preprint that has not undergone peer review. The in vitro findings in cell cultures may not translate directly to in vivo efficacy in living animals. No pharmacokinetic data, dosing recommendations, or safety profiles for baloxavir in cats are provided. The study does not address whether baloxavir crosses the blood-brain barrier effectively to treat the neurological manifestations of feline H5N1 infection.
What different sources said
- bioRxivCenter
Evaluation of antiviral treatments for highly pathogenic avian influenza virus infections in feline species
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