The efficacy of immersion as opposed to oral vaccination of Penaeus indicus larvae against Vibrio harveyi

Significant levels of protection were conferred to Penaeus indicus larvae f or at least 48 h when either fresh or freeze-dried Vibrio harveyi vaccines were administered by immersion, but not when such vaccines were administere d orally. The degree of protection offered increased with the virulence of the pathogen from which the vaccine was made. Vaccination of larvae also in duced cross-protection against challenge by other V. harveyi strains. (C) 1 999 Elsevier Science B.V. All rights reserved.