Wednesday, May 17, 2023

USFWS & USDA Update On Impact of H5N1 on Condors & The Potential Use of HPAI Vaccines


California Condor - Photo Credit Don Graham


Five weeks ago, in in U.S. Fish & Wildlife Service Statement: HPAI Confirmed As Cause Of Death For 3 California Condors, we looked at a preliminary report on the deaths of 3 Condors - and the investigation into additional deaths - in northern Arizona due to HPAI H5N1.

Since then we've seen three updates (herehere & here ) where those numbers continued to climb. As scavenger birds, Condors feed almost exclusively on carrion, which increasingly runs the risk of being infected with HPAI H5 (see USDA Mammalian HPAI Infection List). 

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.

Today there are roughly 500 birds in captivity or in the wild, and H5 avian flu poses a genuine risk to the survival of the species. The latest update from the US Fish & Wildlife Service follows:
The U.S. Fish and Wildlife Service’s Incident Command Team, in collaboration with partner agencies, continues to respond to Highly Pathogenic Avian Influenza (HPAI), also known as bird flu, in the Southwest flock of California condors. Partners and stakeholders are working to enhance supportive care facilities for recovering birds and a newborn chick, maintain support for field operations and monitoring, coordinate with USDA regarding potential vaccination of condors and develop long-term strategies for potential future HPAI outbreaks. 

On March 28, The Peregrine Fund captured a distressed female with an active nest for treatment; she was later confirmed HPAI positive and died. The male diligently continued to incubate the egg; however, there was concern for his health if he continued to stay in the nest cave, which was suspected to be contaminated with HPAI from the female.

Yesterday the USDA announced a pilot program to test an existing HPAI H5 poultry vaccine on vultures (a non-endangered species similar to Condors) in order to determine both its safety, and effectiveness against the currently circulating H5N1 virus. 

While some countries are using existing H5 vaccines to protect their poultry and captive birds against H5N1, the use of older (and potentially poorly matched) vaccines is not without its risks (see WUR: 2 of 4 H5 Poultry Vaccines Tested Appear Effective Against H5N1), which is why the United States, the UK, and many other countries are taking a cautious approach.

Details on this pilot program from the USDA follow: 

USDA Takes Action to Help Protect Endangered California Condors From Highly Pathogenic Avian Influenza

Published: May 16, 2023

The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) is taking emergency action to help protect the critically endangered California condors after several have died from highly pathogenic avian influenza (HPAI). APHIS has approved the emergency use of HPAI vaccine in an attempt to prevent additional deaths of these birds.

The U.S. Fish and Wildlife Service (USFWS) approached APHIS about vaccination after a California condor was found dead in late March and then confirmed positive for HPAI at APHIS’ National Veterinary Services Laboratories. Since then, 13 condors have died and were confirmed to have HPAI, and two others are in recovery at a rehabilitation center.

The authorized vaccine is a killed, inactivated product conditionally licensed by APHIS’ Center for Veterinary Biologics in 2016. Since the vaccine has not previously been tested against this strain of the virus in these species, the first step in the vaccination program is a pilot safety study in North American vultures, a similar species, to investigate if there are any adverse effects before giving the vaccine to the endangered condors. This trial is funded by the U.S Fish and Wildlife Service and will be carried out with the surrogate vultures in North Carolina beginning in May 2023.

APHIS grants emergency use approvals, which exempt products from one or more regulatory requirements normally applied to licensed vaccines, to prevent, control, or eradicate animal diseases in connection with an official USDA program and/or an emergency animal disease situation. APHIS approved this emergency vaccination of the condors because these birds are critically endangered, closely monitored, and their population is very small which allows close monitoring of the vaccine to ensure it is administered only to the approved population. Vultures and California condors are wild birds, not poultry as defined by the World Organization of Animal Health (WOAH), and APHIS does not expect their vaccination to result in impacts to poultry trade.

This emergency use approval is limited to the endangered California condors. USDA Agricultural Research Service scientists continue to research vaccine options that could protect U.S. poultry from HPAI, should vaccination be necessary for additional birds in the United States. Currently, biosecurity measures remain the best, most effective tool for mitigating the virus in commercial flocks, and improved biosecurity measures by the commercial industry have vastly reduced the number of detections compared to previous outbreaks. For example, in March 2022, there were a total of 51 commercial poultry HPAI detections. In March 2023, there were 7 commercial poultry detections, a decrease of 85% from the previous year. In April 2023, there were just two commercial cases of HPAI, compared to 106 cases in April 2022. More information about APHIS’ efforts to work with industry as well as state and other federal partners to manage the outbreak can be found here.