Streptococcus suis is a challenging bacterial pathogen when it comes to swine health since it can cause infections in the brain, joints, heart and lungs of young pigs. Streptococcus suis is a normal inhabitant of the respiratory tract and is found in all swine herds.
However, it becomes a problem when it expresses virulent factors that cause disease. When you have a disease-associated Streptococcus suis (DASS) in your sow herd, the only way to eliminate the pathogenic strain is to complete a depopulation and repopulation of the herd from a source that is negative for DASS.
It is a difficult decision to depopulate and repopulate a herd. A good time to consider it as a viable option is when there is a new disease break in the herd such as porcine reproductive and respiratory syndrome (PRRS) or the bacterial burden of the DASS in combination with other pathogens, like Glaesserella parasuis, that can both cause a significant reduction in production.
Since depopulation and repopulation is a very expensive and not always feasible option, there are tools that we can use to reduce the impact of DASS in our pigs and production. Things to address are immunity, environmental stress reduction, decreased pathogen co-infections and strategic antibiotic therapy.
An Iowa pork producer was struggling with DASS, both at the sow farm and in the nursery. To reduce the burden of this disease, we worked on building immunity within their sow herd and in the piglets. An autogenous vaccine was made to perfectly match the strain of DASS in the herd.
The next thing we did was eliminate environmental stresses like overcrowding, poor ventilation, humidity and poor sanitation. Ventilation was adjusted both in the farrowing rooms as well as the nurseries to ensure that the rooms stayed warm and dry.
The sow farm was also influenza positive. By having the viral co-infection with the DASS, it created the perfect breeding environment in the lungs for the DASS to systemically infect the pig. To reduce DASS impact, an influenza elimination protocol was performed and successfully turned the herd to influenza negative status.
Antibiotics also play an important role in DASS reduction, but need to be used in a strategic manner. The goal is to set up the farm and pigs for success with minimal antibiotic intervention. In this incidence, antibiotics were given to the sows in a one-time pulse to reduce shedding and help stabilize the farm as well as an antibiotic given at processing to help the piglets fight off the natural infection. After implementing these modifications, the producer saw a significant reduction in their DASS burden to their pigs’ health and production.
There is no easy or quick fix for DASS. However, there are many health and management tools that can be utilized to reduce the impact of DASS and improve swine health and production in your herd.
[Source: Farm Journal’s Pork, 27 April 2023, by Rachel Jenson, Pipestone]