Ducks in North America can be carriers of avian influenza viruses similar to those found in a 2016 outbreak in Indiana that led to the losses of hundreds of thousands of chickens and turkeys, according to a recent study.
Understanding the genetic origins of avian influenza outbreaks through enhanced wild bird surveillance sampling can provide early warning to poultry producers, and lead to improved biosecurity measures that can reduce economic losses in future outbreaks.
To understand the origins of the novel strain of H7N8 avian influenza that caused the Indiana outbreak in January 2016, and possible role of wild birds in the outbreak, the USGS and collaborators examined over 400 wild bird viruses from across North America collected between 2007 and 2016.
They found that wild waterfowl, such as ducks and geese, commonly carry avian influenza viruses and typically show no signs of illness. Wild bird viruses can be transferred to commercial poultry through their fecal material when deposited on soil and in water.
“It is really interesting that the study identified diving ducks, such as the Lesser Scaup, as carriers of viruses closely related to those found in poultry,” said Andy Ramey of the U.S. Geological Survey, one of the co-authors of the study. “Diving ducks are not often targeted for influenza sampling.”
“We found that a similar virus circulated among wild ducks in the Mississippi Flyway during autumn 2015, prior to the outbreak in Indiana turkeys,” said Dr. Henry Wan of Mississippi State University, another co-author of the study.
The authors —including researchers from USGS, Mississippi State University, University of Georgia, The Ohio State University, St. Jude Children’s Research Hospital, and the U.S. Department of Agriculture— concluded that diving ducks may serve an important and understudied role in the maintenance and transmission of avian influenza viruses in North America.
Introductions of avian influenza viruses from wild birds to domestic poultry present a continuous threat to the poultry industry. In 2016, the USGS developed a science strategy that focuses on producing science to inform the national surveillance plan, which is coordinated through state and federal agencies across North America, and agency partners responsible for safeguarding U.S. poultry. Samples collected for this study were obtained as part of federal Interagency Wild Bird Surveillance and National Institutes of Health Centers of Excellence for Influenza Research and Surveillance programs. The U.S. Geological Survey conducts research and monitoring of avian diseases to safeguard the Nation’s health, economy, and resources by leading science to understand and minimize exposures to infectious disease agents in the environment.
The new report in the Journal of Virology is entitled, “Low pathogenic influenza A viruses in North American diving ducks contribute to the emergence of a novel highly pathogenic influenza A (H7N8) virus.”