First FWS 2024 Update on California Condor H5N1 Vaccination Trial

California Condor - Photo Credit Don Graham 

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It's been nearly 2 months since we saw the last update (see HERE) on the effort to protect the highly endangered California Condor from HPAI H5N1 using an experimental vaccine. 

As scavengers, Condors feed almost exclusively on carrion, which increases their risk of being exposed to HPAI H5 viruses. With only about 500 birds remaining in captivity or in the wild, avian flu poses a genuine risk to the survival of the species.

Ten months ago we began to see reports of California Condors (all located in Arizona) infected with the HPAI H5N1 virus (see USFWS Update: 21 Condor Deaths Attributed To HPAI H5). In May plans were announced to use H5N1 poultry vaccines to protect these birds, assuming safety tests on non-endangered American Vultures proved successful. 

In late July the FWS announced the start of the California Condor H5N1 Vaccination Trial.

In October's USFWS Update: Early HPAI Vaccine Results From Endangered California Condors, we saw that birds in the first group mounted a modest immune response following vaccination. Not overwhelming, but encouraging enough that the decision was made to expand vaccination to an additional 14 captive birds due for future release.

Today's update indicates that nearly 100 Condors have now received at least one dose of the vaccine, and that a number of infected condors in the wild have apparently survived and now carry antibodies to the virus. 

CALIFORNIA CONDORS & HPAI UPDATE

February 2, 2024

The U.S. Fish and Wildlife Service’s Incident Command Team, in collaboration with partner agencies, continues to develop and implement conservation strategies to help California condors regarding Highly Pathogenic Avian Influenza (HPAI).

Vaccinations

Based on the results of the vaccine trial, the Service determined it is appropriate to move forward with HPAI vaccinations of captively managed and free-flying condors. The Incident Command and recovery partners continue to coordinate on implementing vaccinations.

As of this report, 94 birds have received at least the initial dose of the vaccine. The vaccine is being administered with the prime and boost approach (vaccination of 0.5ml on two occasions a minimum of 21 days apart). All condors are vaccinated by veterinarians licensed in the state according to USDA/State Veterinarian-approved site-specific plans.

Antibody titers collected during the trial indicate the vaccine may reduce the severity of an infection and minimize the likelihood of mortality. Vaccinating condors with the approved vaccine may provide some protection, and even if minimal, it could reduce the amount of mortality and decrease the impact to the flock and recovery efforts if another outbreak were to occur.

Field Operations

The Peregrine Fund conducted winter trapping designed to overlap with hunting season to evaluate lead levels in the Southwest flock in Arizona. During this routine trapping, blood samples were collected to determine whether any of the birds showed antibody titers to HPAI, indicating exposure to the virus. So far, samples from 21 birds have been collected and tested. About half of the samples show natural antibody titers to the H5N1 strain of HPAI meaning the birds were exposed to the virus and naturally survived.

The critically endangered California Condor nearly became extinct in the early 1980s, but has pulled by from the brink due to conservation efforts by the US Fish & Wildlife Service, the National Park Service, and breeding programs at San Diego's Wild Animal Park and the Los Angeles Zoo.

While the vaccine may not be fully protective, hopefully it will provide enough of an advantage that these majestic birds will survive their encounters with the virus in the wild.