For Immediate Release: September 20, 2002

Contact: , American Bird Conservancy, 202/234-7181 ext. 207
, CDC, (404) 639-3286
, AZA, (301) 562-0777 x 240

West Nile Bird Vaccine Breakthrough

American Bird Conservancy (ABC), in partnership with the American Zoo and Aquarium Association (AZA), and with support from Disney Wildlife Conservation Fund, has led efforts to develop a West Nile vaccine for birds. The first round of trials, carried out by The Centers for Disease Control and Prevention (CDC) in Fort Collins, Colorado, have now been completed with encouraging results: inoculated birds showed a 60% increase in survival rates over unvaccinated birds in lab tests.

The virus, first discovered in the U.S. in 1999 has been responsible for approximately 60 human deaths. The toll on both wild and captive birds has been enormous. The response of birds to West Nile is highly species specific, with crows, Blue Jays and hawks among the worst hit. In total 111 species have now been recorded as killed, but because of the elusive behavior of sick birds and the efficiency of scavengers, most dead birds are never found. Those that have reached local laboratories for analysis represent only the smallest fraction of birds actually killed - a number thought to be in the tens of thousands by researchers.

Concern among zoos and captive breeding facilities that some endangered and threatened species both in the wild and those being bred for reintroduction could be impacted, has led to the effort to develop a vaccine.

"We are very pleased with the initial tests and believe this could be an effective tool for protecting some of our most endangered birds such as Mississippi Sandhill Cranes and California Condors," said Dr. Patti Bright, a veterinary epidemiologist, and Director of ABC’s Pesticides and Birds Campaign. "We are now looking forward to conducting field trials at participating institutions to see how the vaccine performs in real-world situations, outside of the laboratory."

The American Crow suffers close to 100% mortality rates in the wild when infected by West Nile virus and so was chosen as the test species for the vaccine trials. At the CDC lab, scientists noted a reduction in mortality rates of 60% by use of the new recombinant DNA vaccine.

Paralleling the development of the recombinant DNA vaccine in the U.S., scientists in Israel (where the disease was first discovered) have been working on a ‘killed’ vaccine, which has also showed early promise in laboratory trials. Concurrently, researchers at CDC, in collaboration with Colorado State University, United States Army Medical Research Institute for Infectious Diseases, Harvard University, and Temple University, are investigating the manufacture of an oral vaccine for use on wild bird populations. Recent successes with injectable vaccines may lead one step closer to this goal.

Additional funding for this project has been provided by several AZA member institutions: including the Dallas Zoo, Brookfield Zoo (Chicago), Franklin Park Zoo (Boston), Houston Zoo, Saint Louis Zoo, and the Wildlife Conservation Society, headquartered at the Bronx Zoo (New York City).