The present invention provides a preferred method for preventing and/or treating a virus infection in aquatic animals, including the steps of: (i) providing a composition including trichoanguin protein; (ii) adding the composition to an aqueous solution including aquatic animals; and (iii) exposing the aquatic animals to the composition; wherein the composition is added in an amount effective to prevent and/or treat the virus infection. Preferably, the trichoanguin protein is provided by a transgenic plant.