How close are we to having a Strep suis vaccine for pigs?

Although antibiotics provide a treatment option for Streptococcus suis — a common, widespread bacterium in swine — long-term management hinges on an effective vaccine.

Add in the prospect of growing limitations on antibiotic use and it’s increasingly important to focus on controlling Strep suis, as well as other pathogens, said Mariela Segura, PhD, immunologist in the pathology and microbiology department at the University of Montreal.

Today, there is no commercial Strep suis vaccine available. Autogenous vaccines are an option, but they’ve produced very mixed results.

More research is needed in all areas. “We need to study the etiology of the disease,” she told Pig Health Today. “We need to monitor the pathogen and better understand how it induces disease and how the host reacts.”

Adding to the challenge are the numerous Strep suis serotypes, or a mix of serotypes, circulating among swine herds. The greatest difference is found between serotypes in North America and those in Europe and Asia, which Segura said are more virulent and present more zoonotic risks. While no more than 10% of the Strep suis in the US can be linked to Europe and Asia strains, it’s important to monitor for any increases or change.

“A vaccine could help protect against different serotypes, but we need more research to identify a vaccine candidate that provides universal coverage,” Segura said.

Another challenge in developing a Strep suis vaccine is to find the right adjuvant to provoke an effective immune response, as well as ensure that it’s safe.

“If we want to vaccinate piglets, we also need to know more about maternal antibodies and the (vaccination) window that we have,” Segura added.

Meanwhile, she acknowledged that North American swine producers and veterinarians have sound protocols in place to dilute the Strep suis impact. Some of these include general biosecurity practices, disinfecting facilities between pig groups and hygiene procedures such as wearing gloves when handling infected pigs.

“Eventually a vaccine is the ideal tool to control this disease,” Segura concluded. “We’re making progress step by step.”