Natural nasal microbes offer broad-spectrum antiviral protection

Respiratory viral diseases, including porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV), represent significant challenges in global pig farming, causing high mortality rates in piglets and economic losses. Current vaccines offer limited protection due to viral mutations and brief immunity, necessitating the development of broader antiviral solutions.

A research team at Nanjing Agricultural University has isolated a strain of Bacillus subtilis (NS12) from the nasal mucosa of outdoor pigs, demonstrating its potential to colonize mucosal surfaces and inhibit viral infections directly. Epidemiological studies indicated that pigs with outdoor access had fewer respiratory viruses, likely linked to higher Bacillus subtilis levels in their nasal cavities.

The NS12 strain can persist in the nasal mucosa for two weeks and produces antiviral metabolites that neutralize numerous enveloped viruses. In trials, NS12 reduced viral loads and tissue damage in piglets affected by PRRSV and PEDV. It also showed effectiveness against pseudorabies virus (PRV) in mouse models.

The metabolites include surfactin derivatives and piceatannol, which form a protective barrier on the nasal mucosal surface, preventing viral entry. Researchers suggest that NS12 could be utilized in intranasal probiotic treatments or as veterinary antiviral agents, with potential applications for human respiratory viruses as well.

• Why it matters: This research could lead to improved disease management in livestock, thereby enhancing global food security and mitigating economic losses in the agricultural sector.
• NS12’s antiviral mechanisms may extend beyond pigs, potentially offering new treatments for human respiratory infections.

• The latest: The study is published in the journal *Research*, detailing the promising results for the further development of NS12-based antiviral strategies.