H5N1 avian flu outbreaks on US dairy farms have decreased significantly over the past few months, but scientists are still studying how the virus spreads on these farms. New research from California outbreak hotspots suggests that airborne aerosols and contaminated wastewater may play a role in the spread of the virus.
Researchers at Emory University conducted experiments on 14 dairy farms across two regions in California, collecting air, farm wastewater, and milk samples to understand how the virus spreads among animals and occasionally to people. Their findings indicate that H5N1 viral RNA can be found in the air on farms and that infectious virus is present during milking.
The study also suggests that contaminated wastewater may serve as a source of spread between cows, to humans, and to peri-domestic animals. Researchers detected H5N1 viral RNA at each point of the waste stream, including manure lagoons widely used by migratory birds and fields with grazing cows.
To combat the spread of the virus, researchers recommend multiple mitigations, including respiratory and ocular protection for farm workers, disinfection of milking equipment, treatment of contaminated milk and wastewater to inactivate the virus, and identification of infected cows, even those not showing clinical symptoms. The findings emphasize the need for a comprehensive approach to prevent H5N1 transmission on dairy farms.
Source: https://www.cidrap.umn.edu/avian-influenza-bird-flu/air-wastewater-may-play-roles-h5n1-transmission-dairy-farms