Geographic distribution of mortality events associated with severe Perkinsea infection (SPI) and detections of Novel Alveolate Group 01 (NAG01) Perkinsea by polymerase chain reaction amplification (PCR) in tadpoles collected from mortality events and health monitoring studies investigated by the U.S. Geological Survey-National Wildlife Health Center (NWHC), and the U.S. Geological Survey Amphibian Research and Monitoring Initiative (ARMI) in the United States, 1999–2015. Grey circles represent sites where SPI associated mortality events took place. Black triangles denote sites where NAG01 Perkinsea was detected in tadpoles collected during the course of amphibian health monitoring studies. Empty triangles represent sites from where apparently normal tadpoles were collected as part of amphibian health monitoring studies and screened for NAG01 Perkinsea with negative results. Map produced using R and the maps package v3.1.140.