Antibodies found in early results from a landmark new vaccine trial are expected to give endangered California condors at least partial protection against deadliest avian influenza strain in American history.
The California condor is the only bird species in the United States that has been approved for the new emergency use vaccine, which was administered this summer to captive-bred condors during a trial at the Los Angeles Zoo Safari Park. of San Diego and the Oregon Zoo.
Officials launched the study after bird flu deaths earlier this year of 21 free-flying condors in Arizona, part of a southwestern flock that typically makes up a third of the wild population.
Wildlife officials feared that the outbreak's toll on the California condor population could erase any progress made in rebuilding the wild population, spurring efforts to speed up vaccinations.
After 40 years of recovery efforts to stave off extinction of the iconic vulture with a 10-foot (3-meter) wingspan, the wild population today numbers fewer than 350 condors in flocks stretching from the Pacific Northwest to Baja California, Mexico. .
“Losing 20 birds is effectively equivalent to setting back the recovery program by 10 years,” said Dr. Hendrik Nollens, vice president of wildlife health for the San Diego Zoo Wildlife Alliance.
The so-called bird flu arrived in the US in February 2022 after wreaking havoc throughout Europe. U.S. agriculture officials consider this year's cases to be part of last year's outbreak, which was recorded as the deadliest ever recorded in the country.
Authorities confirmed the presence of the flu earlier this month in commercial bird flocks in South Dakota and Utah , raising concerns ahead of the spring migratory season. The outbreak cost poultry producers almost 59 million birds in 47 states, including laying hens, turkeys and chickens raised for meat. The flu also caused increases in egg and turkey prices for consumers and cost the federal government more than $660 million.
Early results indicate that when 10 condors were vaccinated with half a milliliter (0.016 fluid ounces) on two occasions (an initial injection and a booster given 21 days later), 60% of the birds showed measurable antibodies that were expected to protect them from avian flu after exposure. .
"We're grateful that we received some immune response," said Ashleigh Blackford, California condor coordinator for the U.S. Fish and Wildlife Service.
The population was nearly wiped out by hunting during the California Gold Rush in the mid-19th century, as well as poisoning by the toxic pesticide DDT and lead ammunition.
In the 1980s, only 22 California condors remained in the wild. They were captured and placed in captive breeding programs to save the species. The zoo-bred birds were first released into the wild in 1992 and have since been reintroduced to habitats from which they had disappeared. The ongoing recovery efforts are considered a conservation success.
Progress on the bird flu trial will allow wildlife officials to move forward and release about two dozen vaccinated condors into the wild in California and Arizona by the end of the year. The government is waiting for additional results before deciding whether free-flying condors should be captured and inoculated. Authorities already vaccinate condors in captivity and in the wild against West Nile virus.
Dr. Carlos Sanchez, director of animal health at the Oregon Zoo, said wildlife officials faced questions about conducting the bird flu vaccine study.
"Human intervention, veterinary intervention, is not something we do all the time or take lightly," he said. "It was not an easy decision".
The injections were initially tested on black vultures to ensure they could be safely injected into condors under managed care starting in July. Post-inoculation monitoring and testing lasted 42 days and officials said no adverse reactions occurred.
Dr. Dominique Keller, chief veterinarian at the Los Angeles Zoo, said participating in the historic trial was one of the highlights of her career. She hopes the condor study will lead to bird flu vaccines for other endangered species.
“It was just incredible to be the first to have the vaccine in my hand and administer it to the first bird,” she said.
The trial's second test group includes 10 condors vaccinated with a single milliliter (0.03 fluid ounce) dose. The results from those birds will determine whether condors in the wild will receive the vaccine.
"We want to look at the data more comprehensively before moving on to what's next," Blackford said.
The condor is intrinsically linked to several Native American tribes in the West and is considered equal or even superior to humans by members of the tribe. The condor disappeared from the ancestral lands of the Yurok tribe in Northern California in the late 19th century, but returned in 2021 after significant conservation efforts by a team led by Tiana Williams-Claussen, director of the wildlife department. of the tribe.
Watching bird flu wipe out 21 birds in Arizona just a few years later was “deeply shocking” to tribal members, Williams-Claussen said. The study and the vaccine could prevent a repeat of the devastation.
"We are all waiting with bated breath to see what the final results will be," he said.