Dr. Orellana is the lead physician for the infectious disease, infection prevention and control, and antimicrobial stewardship programs at Headwaters Health Care Centre. Dr. Orellana is also an infectious disease staff physician at the Cambridge Memorial Hospital, where he sees patients with acute, critical, and cancer-related infections. Additionally, he treats patients living with HIV, Hepatitis, and other sexually transmitted infections at two HIV/AIDS service organizations in Southwestern Ontario.

Dr. Orellana is a graduate of the Ross University School of Medicine. He trained in Internal Medicine and Infectious Disease at the State University of New York—Upstate Medical University, in Syracuse. He is a fellow of the Royal College of Physicians and Surgeons of Canada—certified in internal medicine and infectious disease, a fellow of the American College of Physicians, and a diplomate of the American Board of Internal Medicine. He is a registered member of the College of Physicians and Surgeons of Ontario in good standing. He is fluent in English and Spanish.