Animal Health

Avian Pathogenic E. coli

We have developed an RASV platform antigen delivery system to induce protective immunity to diverse Salmonella serotypes and other enteric bacteria in theEnterobacteriaceae family. This S. Typhimurium strain is being further modified to deliver APEC-specific antigens to induce protective immunity to APEC strains that cause significant mortality and carcass condemnation at slaughter. The use of this Food Safety vaccine will thus have a positive economic benefit to poultry producers.

Necrotic enteritis

Necrotic enteritis results in significant economic losses to the poultry industry, particularly in light of recent efforts to eliminate the use of growth promoting antibiotics when rearing birds.  We are of the opinion that C. perfringens is also responsible for low-grade diarrheas in the developing world and that it is under-reported, so it is also included as part of our enteric diseases program for humans. We have constructed Food Safety RASVs derived from attenuated S. Typhimurium strains designed to induce cross-protective immunity against diverse Salmonella serotypes and protect against C. perfringens colonization and persistence by delivering C. perfringens conserved protective antigens. These Food Safety vaccines can be administered by course spray to newly hatched chicks in the hatchery with a later boost immunization administered in drinking water to chicks on the broiler production facility.

For more information see:

Zekarias, B., H. Mo, and R. Curtiss III. 2008. Recombinant attenuated Salmonella enterica serovar Typhimurium expressing the carboxy-terminal domain from α-toxin from Clostridium perfringens induces protective responses against necrotic enteritis in chickens. Clin. Vaccine Immunol. 15:805-816.

Jiang Y, Mo H, Willingham C, Wang S, Park JY, Kong W, Roland KL, Curtiss R III. 2015. Protection Against Necrotic Enteritis in Broiler Chickens by Regulated Delayed Lysis Salmonella Vaccines. Avian Dis. 59:475-85

Salmonella Choleraesuis and Dublin

S. Choleraesuis and Dublin are associated with enteritis, typhoid, respiratory disease in swine and cattle, respectively. They can also infect humans through the food chain. An RASV could induce cross-protective immunity to both serotypes would be an important Food Safety vaccine.

For more information see:

Kelly SM, Bosecker BA, Curtiss R III. 1992 Characterization and protective properties of attenuated mutants of Salmonella choleraesuis.  Infect Immun. 60:4881-90.

Kennedy MJ, Yancey RJ Jr, Sanchez MS, Rzepkowski RA, Kelly SM, Curtiss R III. 1999.  Attenuation and immunogenicity of Deltacya Deltacrp derivatives of Salmonella choleraesuis in pigs. Infect Immun. 67:4628-36.

Fish Pathogens

The largest aquaculture industry in the United States is the production of channel catfish (Ictalurus punctatus), trout and salmon. The most serious bacterial pathogen affecting this industry are Edwardsiella ictaluri and E.tarda, causing an estimated $50-80 million in annual losses. Our objective is to develop a non-virulent and antibiotic-sensitive E. ictaluri and/or E.tarda strain that will prevent E. ictaluri  and/or E.tarda infections in channel catfish using a bath/oral vaccine along with an economical boost immunization through food. An E. ictaluri vaccine vector can have additional applications for virus/parasite antigen delivery or DNA vaccine delivery for protection against other important pathogens of the aquaculture industry. For additional scientific details and references visit

For more information see:

Santander, J., W. Xin, Z. Yang, and R. Curtiss III. 2010. Aspartate-semialdehyde dehydrogenase (asdA) gene of Edwardsiella ictaluri and its use to develop a balanced-lethal vector-host system for construction of antibioticsensitive live attenuated recombinant vaccines for the catfish aquaculture industry. PLoS ONE 5:e15944.

Santander, J., A. Mitra, and R. Curtiss III. 2011. Phenotype, virulence and immunogenicity of Edwardsiella ictaluri cyclic adenosine 3′,5′-monophosphate receptor protein (Crp) mutants in catfish host. Fish and Shellfish Immunology 31:1142-1153.

Santander, J., G. Golden, S. Y. Wanda, and R. Curtiss III. 2012. The Fur-regulated uptake system of Edwardsiella icataluri and its influence on pathogenesis and immunogenicity in the catfish host. Infect. Immun. 80:2689-2703.

Santander, J., T. Martin, A. Loh, C. Pohlenz, D. M. Gatlin 3rd, and R. Curtiss III. 2013. Mechanisms of intrinsic resistance to antimicrobial peptides of Edwardsiella ictaluri and its influence on fish gut inflammation and virulence. Microbiology 159:1471-1486.

Santander, J., J. Kilbourne, J-Y. Park, T. Martin, A. Loh, I. Diaz, R. Rojas, C. Segovia, D. Denardo and R. Curtiss, III. 2014. Inflammatory effects of Edwardsiella ictaluri lipopolysaccharide modifications in catfish gut. Infect. Immun. 82:3394-3404.