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Vaccines not protecting farmed fish from disease

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The vaccines used by commercial fish farmers are not protecting fish from disease, according to a new study.

The study was compiled by researchers at the University of Waterloo, the Pontifical Catholic University of Valparaiso and Chile’s University of Valparaiso. It showed vaccinated fish tend to show more symptoms when contracting diseases, with the health impacts and ultimately deaths occurring as if they’d never received a vaccine.

The vaccines used by commercial fish farmers are not protecting fish from disease, according to a new study.

The study was compiled by researchers at the University of Waterloo, the Pontifical Catholic University of Valparaiso and Chile’s University of Valparaiso. It showed vaccinated fish tend to show more symptoms when contracting diseases, with the health impacts and ultimately deaths occurring as if they’d never received a vaccine.

“Today’s vaccines are marketed to fish farms as necessary disease prevention and are even required by some insurance companies, but they are not nearly as effective as needed under real world conditions.” said Brian Dixon, a professor in biology at Waterloo. “Some operators are giving five vaccinations per fish and then there are fish losses from the stress of receiving multiple handlings and injections.”

In the study, the researchers tested the efficacy of the vaccine for the bacterial pathogen Piscirickettsia salmonis by comparing the reaction of vaccinated and non-vaccinated Atlantic salmon when exposed to the sea louse Caligus rogercresseyi in the lab.

Continue reading at University of Waterloo

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