The US Fish and Wildlife Service (USFWS) has shared early results from a historic vaccine trial for highly pathogenic avian influenza (HPAI) in condors in California. Results from the first trial group showed that 60 percent of the condors produced measurable antibodies that are expected to provide partial protection against mortality from HPAI if the birds are exposed.
The test, developed in coordination with the USFWS, the US Department of Agriculture (USDA) and the US Geological Service, was conducted at the Los Angeles Zoo in Los Angeles, Calif.; San Diego Zoo Wildlife Alliance in San Diego, Calif.; and the Oregon Zoo in Portland, Ore.; as a longtime partner with the California Condor Recovery Program, and with a new recovery partner, the Carolina Raptor Center in Huntersville, NC
“We are grateful to be working with such high-caliber professionals as we evaluate this vaccine for potential use to mitigate the effects of HPAI on condor recovery efforts,” said the California Condor Recovery Program Coordinator for USFWS, Ashleigh Blackford. “Collaboration with our zoological partners is essential for the implementation of this trial, and their continued support is essential for the implementation of the first vaccines in pre-release condors this fall and winter. None of this important work would be possible without the collaboration of all our partners.”
HPAI was detected in condors in Arizona in early April, with 21 condor deaths recorded in this outbreak. In May, the USDA’s Animal and Plant Health Inspection Service approved the emergency use of a vaccine against HPAI to be piloted on California’s critically endangered condors in managed care. These first results from the Los Angeles Zoo and San Diego Zoo Wildlife Alliance show that the vaccine may benefit free-flying California condors. The USFWS will determine whether to vaccinate the free-flying condors after receiving the final results of the tests.
Each zoo worked closely with the USFWS veterinarian, USDA, and state veterinarians to obtain approval to participate in this first trial of HPAI vaccines in the United States for wild birds. The trial evaluated two vaccination methods—a single dose (1 ml) and an initial dose with a booster shot (0.5 ml in two doses). Animal health company Zoetis developed and manufactured the vaccine.
Twenty-five condors spread across three zoos were identified for participation based on the bird’s age, gender, genetics, and other factors. Of those 25, ten condors received two doses of the vaccine, ten condors received one vaccination, and five condors served as the control group.
The first results were shared, and the USFWS decision to vaccinate the pre-release birds this year was based on the group that received two doses of the vaccine. The presence and degree of immune response to the vaccine were evaluated using the hemagglutination inhibition assay, an antibody detection test, performed by the USDA’s Southeast Poultry Research Laboratory.
Vaccine testing first began with a surrogate species, black vultures, hosted at the Carolina Raptor Center in North Carolina. This step in testing indicates that the vaccine is safe for vulture species, and with expert input, trials can continue with condors.
After confirming the safety of the vaccine with the surrogate species, on July 18, the USFWS, Los Angeles Zoo veterinarians, and zoo team vaccinated the first three condors to evaluate their response. After confirming that there were no adverse reactions in the condors, the Los Angeles Zoo, San Diego Zoo Wildlife Alliance, and Oregon Zoo vaccinated 17 more birds.
“The importance of finding an effective vaccine to protect California condors cannot be overstated,” said Director of Animal Health at the Oregon Zoo, Dr. Carlos Sanchez. “This is a species that, not too long ago, was on the verge of extinction. There are just over 300 individuals in the wild, and this year, within a few weeks, HPAI wiped out 21 of them. If left unchecked, the disease can wipe out decades of conservation work in the blink of an eye.”
California’s condor recovery program has long been an example of how collaboration can help improve the recovery of endangered species. The effort to protect condors against HPAI highlights the value of partnerships once again that include new and novel partners and creative ideas to work towards a successful recovery.