It’s coming – probably – and hopefully, the U.S. poultry industry will be better prepared for the second onslaught of bird flu.
The first wave of the H5N virus emerged late last year in British Columbia flocks. It eventually spread across the Western states to the Upper Midwest, and south to the mid-Mississippi Valley, impacting more than 80 commercial poultry facilities and some forcing the destruction of some 30 million birds.
The disease is thought to be spread by dissemination of the droppings of wild fowl, which are relatively unaffected by it. It was first discovered in the U.S. in a backyard flock in Oregon.
Bruce Holland, director of the Arkansas Livestock and Poultry Commission said that Extension Veterinarian Dustan Clark has been doing a lot of outreach with the backyard producers, educating them what to expect in case of an outbreak, and what to look for in their flocks, and what precautions they can take to keep the influenza out of their birds.
The agency has also been meeting with representatives of the commercial industry to discuss proper biosecurity guidelines. They emphasize points like site security, sanitation, traffic controls and animals.
University of Missouri Veterinary Pathobiology Professor Daniel Shaw told OFN. Shaw, who heads the Avian Section of the school’s Veterinary Medical Diagnostic Lab, said past outbreaks of highly-pathogenic avian influenza were typically isolated to a few areas, which would be quarantined, the birds tested, and the positives euthanized. This time, there were 40 infected premises in Minnesota alone.
The traditional formula was more successful in Missouri, which identified only three infected flocks, two on commercial farms. But for hard hit states like Minnesota and Iowa, it was a very different scenario.
“Now that they know what can happen, we expect that it’ll be able to be stopped a lot more easily. Plus, producers are educated and very sensitive about the possibility of getting something like this into their flocks again, and are being very careful right now,” Shaw said.
The H5N2 strain was also different in its elevated pathogenicity, or percentage of birds sickened and killed. The method of its distribution is still under debate; Shaw said while there’s suspicion it can be carried by the wind, the pattern last spring pointed to the virus being carried by people and equipment, so restricting movement between farms has been a point of emphasis.
Labs like Shaw’s have also become more efficient about getting the testing done quickly and accurately. The PCR (polymerase chain reaction) assay now in use is state-of-the-art and very sensitive. When a state laboratory finds a positive, samples are sent to the National Veterinary Services Laboratory in Ames, Iowa for confirmation. The test is so robust, he said, faith in the results at the local level has grown, and agencies can mobilize the quarantine and cleanup more quickly.
The pattern of spring infections followed known wild bird flyway routes, and authorities suspect there will be more cases this fall.
“When we start seeing those birds come back south for the winter, we expect that they will still be carrying the influenza,” Holland said. “That’s when it becomes more important to do the biosecurity.”
He said the virus prefers cooler temperatures, and authorities suspect the unusually warm fall has kept it down.
Arkansas only had one confirmed case this spring, but ALPC continues fielding calls reporting unusual bird mortality. Holland said most of them come from backyard operators, whose flocks tend to be exposed to the outdoors.
Shaw said there’s no indication domestic fowl have developed any resistance to the strain; although that could happen as a result of mutation or genetic changes in the virus.
