Zoetis Inc. has obtained a conditional license from the U.S. Department of Agriculture (USDA) to market the first commercially available vaccine for helping reduce disease caused by the Georgia 2008 variant of infectious bronchitis virus (IBV) in poultry*. The vaccine is now available in Alabama, Florida, Georgia, Kentucky and Tennessee.
The USDA agreed to issue a conditional license because the modified-live vaccine fills a special need, has been shown to be safe and has demonstrated a "reasonable expectation of efficacy" against the target pathogen.
"The Georgia '08 variant has had a devastating impact on animal health, production, and profits on affected farms, with previously available vaccines providing little protection," said Kalen Cookson, DVM, MAM, a technical services veterinarian for Zoetis.
"We set the ambitious goal in spring 2013 of having a commercial vaccine available for this contagious and costly strain in time for winter, when IBV is most prevalent. We were able to achieve this goal in only seven months, thanks to the strong support of industry and the USDA. We look forward to their continued support as we work towards a full license for the vaccine."
First identified in Georgia in December 2007, the Georgia '08 IBV variant has since been isolated on farms in Alabama, Tennessee and Kentucky. Over the past two winters, its incidence and severity have increased dramatically, resulting in significant losses due to condemnations at processing, reduced line efficiency and additional plant measures needed to process affected birds.
Unlike other IBV strains, which typically affect the upper respiratory tract, the Georgia '08 variant primarily affects the lower tract, particularly the air sacs. According to Cookson, lower respiratory tract infections produce fewer visible symptoms in live birds, but cause "unpleasant surprises" at processing.
"Airsacculitis is a major cause of condemnation," he explained. "Even when birds are salvageable, the extra time and steps required have a major impact on plant efficiency."
In addition, he said, more severe outbreaks of the Georgia '08 strain can cause further losses due to mortalities and secondary infections from E. coli and other harmful bacteria.
The new conditionally licensed vaccine has received broad industry support, including a letter from veterinarians at four major poultry companies affected by the Georgia '08 variant.
Zoetis plans to submit additional efficacy studies of the vaccine in order to pursue a full USDA license. For more information about the conditionally licensed vaccine and other biologicals for managing IBV, producers should contact their local Zoetis representative.
* This product license is conditional. Efficacy and potency test studies are in progress.