At a two-day summit hosted in one of the nation’s top poultry states, researchers and educators from across the Americas discussed efforts to find ways to manage the spread of highly pathogenic avian influenza, a disease that has cost the poultry industry millions of birds across five continents.
The International Avian Influenza Summit was hosted Oct. 16-17 by the Center of Excellence for Poultry Science and the Arkansas Agricultural Experiment Station, part of the University of Arkansas System Division of Agriculture. The summit drew 1,842 registrations from 81 countries. The wide-ranging agenda featured presenters from Mexico, Chile, Scotland, the United States and other countries.
2023-INTERNATIONAL AVIAN INFLUENZA SUMMIT
Since 2021, a very deadly strain of avian influenza called H5N1, has been circulating and affecting millions of birds and mammals around the world.
“We are experiencing one of the most deadly bird flu outbreaks ever,” said Deacue Fields, head of the Division of Agriculture. “This outbreak has cost U.S. poultry producers nearly 59 million birds across 47 states. There was a tremendous economic impact from this outbreak. We saw extremely high egg prices and also turkey prices.
It’s important to come together now and be proactive in discussing the strategies that we can look to, to mitigate further spread of this terrible disease.” Guillermo Tellez-Isaias, a research professor at the Center of Excellence for Poultry Science, organized the summit.
“We can make a global impact on avian influenza,” Tellez-Isaias said. “Your contributions will mean a more resilient future.”
SAMPLING TO MONITOR SPREAD
Among the first day’s presenters was Julianna Lenoch, national coordinator wildlife services for National Wildlife Disease Program at APHIS — the Animal & Plant Health Inspection Service. Lenoch described efforts to monitor movement of the disease through migratory birds and other means.
The APHIS surveillance team restarted its efforts in May after a pause during the breeding period of the sampled birds.
“ We’ re a b o ut fo u r months into the surveillance right now. Our team, as of last week, had already collected about 13,000 samples,” she said. “Our target this year will be to get to almost 42,000 samples.” She said that in the birds sampled in spring of 2022, “around 7 percent of them were coming positive. We were running just shy of 1.9 percent in the winter of 2023 so a pretty dramatic drop in the apparent prevalence.
She said that samples collected from May to August of 2022 showed a 3 percent prevalence of avian influenza. During the same period in 2023, she said there was a “much lower prevalence” despite getting more than 7,000 samples.
“We only found H5N1 in a total of 10 birds during that period,” Lenoch said. “So, either we were sampling in different regions, or there’s simply not as much avian influenza circulating, or we may be looking at a little bit of a tipping point where some of our wild bird species — at least the dabbling ducks — may be developing some immunity.” “Unfortunately, we are starting to see pickup both in our surveillance samples and our domestic side,” Lenoch said. “So avian influenza is starting to trickle in again here in the United States.” Highly pathogenic avian influenza has been confirmed this year in commercial and/or small flocks in Oklahoma, Colorado, Montana, Utah, Idaho, South Dakota, North Dakota, and Minnesota.
AVIAN FLU IN MAMMALS
The sampling has found avian influenza in mammals as well, despite the U.S. lacking a national surveillance system for mammals. Currently, mammalian samples are “opportunistic,” coming from wildlife rehabilitation centers or state wildlife and natural resource agencies.
“Many of these animals have been neurologically affected, and a good portion of them are juveniles or young of the year,” Lenoch. “In the U.S. we’re approaching almost 200 individual detections and mammals we have had a wide breadth of species affected.” These include coyotes, foxes, skunks and raccoons. Avian influenza has also appeared in marine mammals such as seals and a bottle-nose dolphin.
“The leading theory is that likely many of these terrestrial mammals are likely eating sick or dead birds in the environment,” she said.
VACCINATING POULTRY FOR HPAI
Some countries, such as France, have begun vaccinating poultry against HPAI. On Sept. 29, APHIS placed restrictions on importation of poultry from France including ducks, duck eggs and other duck products.
“The restrictions are based on the World Organisation for Animal Health’s definition of poultry and are the result of France’s d e c i s i o n to va cc i n ate commercial meat ducks against HPAI,” APHIS said. “France’s decision to vaccinate presents a risk of introducing HPAI into the United States.” However, Brian Umber-son of the microbial security company Ancera, said attitudes about HPAI vaccination may be changing.
“We’re starting to see the development of a positive view of using vaccinations because of the size of these outbreaks and the shock to the food supply,” he said.
RISK FACTORS FOR HPAI ON THE FARM
On Day 2, Alice Green, veterinary epidemiology officer for USDA, discussed a study that identified factors that increased the risk of infection on turkey farms.
Other factors “associated with increased odds of H5N1 HPI infection included having both brooder and grower turkey production on the farm,” Green said.
Having tom turkeys on the farm and seeing wild waterfowl or shorebirds in the closest field was also associated with increased odds.
“Proximity to water and wild bird habitat, as well as presence of high densities of migratory wild waterfowl, have been identified as risk factors in previous outbreaks concentrations of domestic poultry in combination with high densities of wild birds provides a potential interface for viral transmission and spillover events,” Green said.
There are human factors as well. The study found that having a restroom — even a portable one and having access to a shower — were found to be protective factors.
SURVEILLANCE AS AN EARLY WARNING SYSTEM
Pedro Jimenez-Bluhm, assistant professor, Pontificia Universidad Católica de Chile, discussed wild bird sampling efforts in Chile, at the southern end of the Pacific Flyway.
Starting in August 2022, “ we d i s cove re d s o m e low-pathogenic viruses, but then we had this huge peak at the end of the year,” he said. “That’s where we started seeing H5N1-positive samples.
“Through this environmental sampling, in this case, we were actually able to get the positive (confirmation) one week before people were announcing mortalities,” Jimenez-Bluhm said, adding that this makes a lot of sense because “there needs to be a certain viral load in the environment for animals to actually efficiently transmit this virus. So, this is a very sensitive way to actually detect the pathogen in the environment.” Closing out the second day were presentations on strategies for developing vaccines for this virus strain, genome editing to examine avian influenza resistance in chickens and a presentation from Tellez-Isaias on “CRISPR and Quorum Sensing as strategic control measurements for Avian Influenza Virus.” To learn about extension programs in Arkansas, contact a local Cooperative Extension Service agent or visit www.uaex.uada.edu. Follow the agency on Twitter and Instagram at @ AR_Extension.
Mary Hightower is with the University of Arkansas System Division of Agriculture.