Low-density Waterfowl in California Wetlands

Waterfowl in California can spread the avian influenza virus (AIv) during summertime when wetland temperatures are warm and waterfowl densities are low.

Researchers with the USGS and partners found low pathogenic (LP) AIv in water and waterfowl fecal samples collected in the California Central Valley during summer, indicating on-going infections in resident waterfowl, persistent shedding and active transmission of AIv.

Despite previous research suggesting that colder temperatures and increased bird densities as waterfowl congregate during migration are most favorable to the survival of these viruses, the recent findings suggest that high summer water temperatures do not prevent its circulation.