Developing a vaccine for Strep suis is proving to be a challenge

Although several groups are working on the development of vaccines to protect pigs from Strep suis, the task is proving to be particularly challenging.

4 April 2019, at 11:19am

Strep suis is a Gram-positive bacteria that typically colonises the throat, respiratory tract and gut of the pig and is common throughout the pork sector world wide.

Dr Matheus Costa, an Adjunct Professor with the University of Saskatchewan's Western College of Veterinary Medicine and an Assistant Professor with the University of Minnesota, says there are many different groups world wide working on vaccines for Strep suis but developing a vaccine for this infection is very challenging.

In an interview with Farmscape.Ca, Dr Costa explains that Strep suis is a dynamic pathogen which makes prevention and treatment very difficult:

"Strep suis or Streptococcus suis actually has over 100 genes associated with virulence factors. What this means is that basically Streptococcus suis is a solider and it has over 100 guns to use when invading the pig's body. Every time we take one gun down, the pathogen will pull a different one and use it.

"It is very challenging to develop a vaccine against a bacteria that has so many guns to use.

"There are many groups exploring different vaccine candidates. There are different genes being identified almost on a yearly basis that are associated with disease but the fact they have over 100 virulence genes makes it very challenging for us to identify the one that will cross protect against all different Streptococcus suis.

"This is another important aspect of this pathogen. There is not just one kind. There are over 35 different kinds and each one of them will express those 100 different genes in a different way so the combinations are so many.

"That's probably the best explanation why some autogenous vaccines don't work so well."

Dr Costa says a particular vaccine approach that may be on the horizon isn't really clear. He says, in the next five to ten years there may be but "we're not there yet".