Evaluation of a prototype vaccine for rattles in foals

Rattles is a severe and potentially fatal disease of Thoroughbred foals, caused by the bacterium Rhodococcus equi. As the bacterium is present in virtually all soils it is very difficult to prevent foals from being exposed to it. Up to 20% of foals exposed to the bacterium will develop severe pneumonia known as rattles. These severe cases will require veterinary intervention and likely be treated using a combination of antibiotics. Approximately 28% of foals affected by rattles will die from the disease. This project aims to develop an mRNA-based vaccine to protect foals from rattles. Previous adenovirus-based prototypes were effective but not commercially viable at scale, prompting a shift to mRNA technology for its ease of production and strong immune response. The study will test two dose strategies in foals, assessing safety, antibody production, and cellular immunity. After the successful completion of this project, the vaccine performance data will be used to recruit a veterinary health company to undertake the further development and commercialisation processes to deliver it to the Australian Thoroughbred industry.