Some types of salmonella cause disease in food animals like pigs, and others cause foodborne illness in people. A new vaccine developed by scientists with the Agricultural Research Service (ARS) in Ames, Iowa, protects against both of these types of salmonella in food animals.
Most salmonella vaccines only protect against one type of the pathogen, ARS said, which leaves pigs susceptible to disease from other salmonella pathogens. While some salmonella vaccines reduce disease in pigs, they may not protect against salmonella that causes foodborne illness in people.
Microbiologists Shawn Bearson with the ARS Food Safety & Enteric Pathogens Research Unit and Brad Bearson with the ARS Agroecosystems Management Research Unit developed a new vaccine that protects food animals against both human and animal disease-causing salmonella.
In experiments, the vaccine protected pigs against two types: Salmonella typhimurium and Salmonella choleraesuis. It also protected turkeys against S. typhimurium and the multi-drug-resistant Salmonella heidelberg — the bacterium responsible for a 2011 outbreak in ground turkey.
S. choleraesuis, the source of major U.S. and global outbreaks in swine in the 1980s and 1990s, causes a severe disease that can kill animals. According to ARS scientists, if an outbreak occurs in the U.S., the new vaccine could provide protection against S. choleraesuis, along with other foodborne salmonella strains such as S. typhimurium.
ARS said the vaccine also falls under the category "differentiation of infected from vaccinated animals," meaning it shouldn't interfere with specific tests used to detect natural salmonella infections in pigs. Thus, a producer can differentiate vaccinated animals from those naturally exposed to salmonella.
"We tried to design the vaccine to address the needs of the swine industry. In doing so, not only did we develop a vaccine that is not salmonella type specific, but we also made one that's not food animal species specific," Brad Bearson said.
The scientists believe that the vaccine will protect against other types of salmonella in addition to the three strains tested. ARS has filed a patent application for this vaccine technology.