Participants at the Burning Seed festival were looking for a good time but instead could have contracted meningococcal.
An attendee was confirmed to have threatening disease.
The NSW Public Health Unit identified the person’s close contacts and provided assistance but participants have been warned.
Anyone feeling unwell or experiencing any symptoms, which include fever, joint and muscle pain, nausea, vomiting, headaches, tiredness and rash, are urged to go to hospital.
