Vaccine for swine dysentery is ‘within reach’ – scientists

Researchers say they are a step closer to a vaccine for swine dysentery – the devastating bacterial disease which causes severe losses and piglet mortality.

Swine dysentery causes damage to the enteric system of pigs, resulting in severe diarrhoea and weight loss. Although not a notifiable disease, producers are encouraged to report cases to the Agriculture and Horticulture Development Board.

Researchers at the Western College of Veterinary Medicine (WCVM) in Canada are optimistic that a vaccine is within their reach.

They are using DNA sequencing technology to investigate the disease mechanism of swine dysentery.

Led by Matheus Costa at the WCVM’s Department of Large Animal Clinical Sciences at Saskatchewan University, the team is focused on Brachyspira bacteria, the culprit behind swine dysentery.

Brachyspira infects a pig’s large intestine and causes lesions, which results in watery or mucoid diarrhoea — often with traces of blood.

As the affected pigs get sick, they lose their appetites and become dehydrated and thin.

“If we understand exactly how Brachyspira infection leads to swine dysentery, we’ll have a better chance at making a vaccine that works,” says Dr Costsa. “We’ll also get a better chance to develop other tools – non-antibiotic alternatives that will prevent disease.”

Antibodies

One ongoing project for understanding the disease mechanism is investigating the pathway by which Brachyspira affects the response of B cells — the cells responsible for producing antibodies.

Since vaccines are typically aimed at stimulating B cells to produce these antibodies and the scientists have learned that Brachyspira affects B cell activation, they’re looking for a different approach to developing vaccines for swine dysentery.

“Now, we have much better methods, and we understand the molecular changes that happen in the colon and the pig in general. So, we’re in a better place to develop a vaccine that will be efficient and that will protect pigs, or at least prevent severe disease.”

The AHDB says biosecurity is key to prevent and control swine dysentery. Producers should watch out for clinical signs and report them immediately and join the AHDB Significant Diseases Charter to be notified of any local outbreaks.