THE DEVELOPMENT OF ORAL VACCINES AGAINST PARASITIC DISEASES UTILIZINGLIVER ATTENUATED SALMONELLA

Genetically defined, live attenuated Salmollella vaccines are proving useful both as oral vaccines against salmonellosis and for the develop ment of multivalent vaccines based on the expression of heterologous a ntigens in such strains. Several candidate attenuated S. typhi strains are at present being evaluated as new single dose oral typhoid vaccin es in human volunteers. The emergence of such a vaccine will facilitat e the development of multivalent vaccines for humans. Many antigens fr om different infectious organisms have been expressed in attenuated Sa lmonella. A focus of this work has been on developing vaccines against parasitic diseases. This review will summarize the efforts that have been made in this area.