Encapsulated vaccines for the oral vaccination and boostering of fish and other animals

1. A composition for oral administration to an animal for intestinal delivery of a pharmaceutically active agent, said composition comprising: a) at least one bioadhesive polymer selected from the group consisting of chitosan, hyaluronic acid, cationic guar, and combinations thereof; wherein the bioadhesive polymer is present at a concentration of between 1% and 10%; b) at least one oligosaccharide selected from the group consisting of inulin, fructooligosaccharide and dextrin, wherein the oligosaccharide is present at a concentration of between 1% and 50%; c) at least one mediating compound having both hydrophilic and lipophilic properties, wherein the mediating compound comprises an emulsifier/sugar complex containing 0.5 to 12.5% w/w emulsifier and 5-30% w/w sugar, and d) a pharmaceutically active agent.

2. The composition of claim 1 , wherein the mediating compound comprises at least one emulsifier selected from the group consisting of monoglycerides, sorbitan esters, propylene glycol esters, lecithin, polysorbates and sucrose esters, and/or at least one sugar selected from the group consisting of glucose, sucrose and trehalose.

3. The composition of claim 2 , wherein the mediating compound is present at a concentration of between 0.1% and 50%.

4. The composition of claim 1 , wherein the pharmaceutically active agent is selected from immunogenic peptides and proteins including recombinant vectors to deliver and express genes encoding immunogenic proteins, intact inactive, attenuated and infectious viral particles; intact killed, attenuated and infectious prokaryotes; intact killed, attenuated and infectious protozoans and intact killed, attenuated and infectious multicellular pathogens.

5. The composition of claim 1 , wherein the pharmaceutically active agent is a Salmon Rickettsial Septicaemia (SRS) vaccine.

6. A composition for stabilizing and delivery of a pharmaceutically active agent to the gut of a fish, the composition comprising chitosan and inulin in combination with an emulsifier/sugar complex wherein the emulsifier/sugar complex comprises 0.5 to 12.5% w/w emulsifier and 5-30% w/w sugar, wherein the emulsifier/sugar complex comprises lecithin and is in an amount sufficient to mediate the interaction between inulin and the hydrophobic amine residues of chitosan, and wherein the pharmaceutically active agent is a Salmon Rickettsial Septicaemia (SRS) vaccine.

7. A method for oral vaccination of an animal for intestinal delivery of a pharmaceutically active agent, comprising:

orally administering to the animal a composition according to claim 1 .

8. The method of claim 7 , wherein the vaccinated animal is a fish, mammal or bird.

9. The method of claim 8 , wherein the fish is a salmonid.

10. The method of claim 9 , wherein the oral vaccine comprises a Salmon Rickettsial Septicaemia (SRS) vaccine.

11. The composition of claim 1 , wherein the composition is sized for oral delivery and having a particle size from about 10 um to 200 um.