Location: Cool and Cold Water Aquaculture ResearchTitle: Efficacy testing of 35-year-old commercially-produced ERM bacterin reveals the remarkable stability of this product Author
|Welch, Timothy - Tim|
|Goodrich, Thomas - Aqua Tactics Fish Health & Vaccines|
|La Patra, Scott - Clear Springs Foods, Inc|
Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2017
Publication Date: 5/26/2017
Citation: Welch, T.J., Goodrich, T.D., La Patra, S.E. 2017. Efficacy testing of 35-year-old commercially-produced ERM bacterin reveals the remarkable stability of this product. Journal of Fish Diseases. 00:1–4. doi:10.1111/jfd.12646.
Interpretive Summary: Infectious diseases are a major impediment to production efficiency and animal welfare in commercial aquaculture. In the 1970's a highly effective vaccine was developed to prevent disease caused by the salmonid bacterial pathogen Yersinia ruckeri and this vaccine became the first biological product licensed by the United States Department of Agriculture for use on fish. This vaccine is exceptionally potent and it is this property that is likely the reason for the widespread use and commercial success of this product. We recently found a 35-year-old bottle of Y. ruckeri vaccine in a storage closet at Clear Springs Foods. The vaccine was produced by Wildlife Vaccines, has an expiration date of October 18, 1982 and had likely been stored at room temperature since that time. This bottle was part of one the first commercial lots of this vaccine produced soon after its licensure and field trials completed in the late 1970s. In this study, we perform immunological and efficacy studies which demonstrate that the vaccine confers protection against experimental challenge despite it being expired well over 30 years ago. These results further demonstrate the high potency and remarkable stability of this vaccine.
Technical Abstract: Recently, a bottle of ERM bacterin that was approximately 35-years-old and labeled by Wildlife Vaccines with a serial number of 236 and an expiration date of October 18, 1982 was discovered in a storage closet at room temperature at the Clear Springs Foods Research Division. Microscopic evaluation after Diff-Quick staining revealed intact cells clearly evident after 35 years of room temperature storage. Additional immunological evaluation indicated that cells present in this 35-year-old ERB vaccine preparation display antigenically intact lipopolysaccharide (LPS). Since LPS is known to be the protective component of this vaccine we hypothesized that this long expired preparation would still confer protection. In-vivo testing in juvenile rainbow trout (mean weight, 3.5 g) using the old Wildlife Vaccine product and a fresh ERM vaccine produced in-house at Clear Springs demonstrated that injection delivery of the 35-year-old ERB vaccine resulted in essentially complete protection under conditions that resulted in 60% mortality in the unvaccinated controls. In addition, immersion vaccination with the ERB vaccine also resulted in significant protection, although the level of protection was lower than that of injection vaccination of the ERB vaccine and lower than immersion or injection delivery of the fresh vaccine preparation. These results further highlight the high potency and stability of this vaccine, properties which have been important for the resounding success of this product.