A US Public Health Service Commissioned Corps Response to a Syphilis Outbreak in Tribal Communities in South Dakota and North Dakota, 2025.

From January 5 through April 4, 2025, and July 14 through October 10, 2025, the US Public Health Service Commissioned Corps conducted the largest reported deployment in response to a syphilis outbreak in US history. During two 90-day periods, 67 US Public Health Service officers were deployed in 30-day rotations across 9 Tribal areas within the Indian Health Service Great Plains Area and 3 urban centers in South Dakota and North Dakota to support ongoing outbreak activities. Overall, the deployment identified 139 people newly diagnosed with syphilis through screening 2913 people. By 30 days after deployments for the syphilis outbreak response, 126 (90.6%) people with newly diagnosed syphilis had started treatment. This case study highlights the effective coordination among the Indian Health Service, the US Public Health Service Commissioned Corps, state health departments, Tribal health agencies, the Great Plains Tribal Leaders Health Board, and other partners. Prioritized activities of the response included contact tracing, health care provider education, community-based screening events, and field-based administration of treatment. We describe the roles of culturally sensitive public health practice, interagency collaboration, and rapid clinical response in responding to sexually transmitted infection outbreaks. Experience gained in South Dakota and North Dakota may provide insightful direction for future large-scale infectious disease campaigns.