Oral interferon alpha treatment significantly reduces halitosis and Porphyromonas gulae growth in dogs with periodontal disease

Periodontal disease (PD) is one of the most common infectious conditions in dogs, associated with plaque accumulation, gingival inflammation, halitosis, and tooth loss. Halitosis is primarily caused by volatile sulfur compounds (VSCs) generated by anaerobic bacteria, including Porphyromonas gulae ( P. gulae ), a pathogen closely linked to PD progression. This study examined the effects of oral interferon alpha (IFN-α) on halitosis and bacterial activity in dogs with PD. Thirty-two dogs with moderate-to-severe PD were enrolled and allocated to untreated controls (n=10) or IFN-α treatment (n=22). Dogs in the treatment group received 2.75 g of IFN-α formulation (InterBerryα®) applied to the gingival margin twice weekly for five weeks. Clinical outcomes included PD Severity Index, enzymatic activity to hydrolyze N-benzoyl-DL-arginine-naphthylamide (BANA), PCR detection of P. gulae , and halitosis evaluation by gas chromatography and pet owner assessment. IFN-α significantly reduced PD Severity Index, BANA activity, and VSC concentrations (hydrogen sulfide and methyl mercaptan) compared with baseline and controls. Additionally, 27% of treated dogs converted to P. gulae -negative status after therapy. Owners reported marked improvement in oral malodor. These findings suggest that oral IFN-α effectively alleviates halitosis and reduces periodontal pathogen activity, supporting its potential as a non-invasive treatment for canine PD. • Oral interferon-α (IFN-α) therapy alleviated halitosis in dogs with periodontal disease. • Five-week IFN-α treatment significantly reduced gingival inflammation and BANA activity. • IFN-α lowered concentrations of volatile sulfur compounds linked to oral malodor. • Twenty-seven percent of treated dogs converted to Porphyromonas gulae -negative status. • IFN-α may serve as a non-invasive adjunctive approach for managing periodontal disease–associated clinical signs in dogs.