Abstract: A recombinant vaccine that is useful for immunizing fish against ciliated ectoparasitic protozoans that cause white spot disease also known as ‘ich’. The disease is caused by Ichthyophthirius multifiliis which is a ciliated ectorparasitic protozoan that is an obligate parasite and therefore cannot grow in vitro. The instant vaccine replaces chemotherapy and vaccines prepared from I. Multifiliis production in live fish. The effective element of the vaccine is a recombinant fusion protein derived from an artificial DNA sequence for immobilization antigen, repeat I, of Ichthyophthirius multifiliis. The novel DNA nucleotide and amino acid sequences are disclosed.

Abstract: A composition for oral immunization comprising recombinant proteins AHMA and FP that afford protection from bacteria and protozoan ectoparasites respectively is disclosed. Also disclosed are compositions that have in addition, inactivated viruses and killed bacteria affording a wider spectrum of protection against infections that predominantly afflict aquatic species. Method of making these compositions and administering them either directly or by incorporating them into feed, as also the use of such compositions for treating animals in need of such treatment are also disclosed.