O157:H7 Cluster Associated With Deer Harvested at a Single Wildlife Hunting Area, Oregon, 2017

The Oregon Health Authority routinely investigates clusters of reportable enteric diseases identified by whole-genome sequencing. While investigating 2 cases of O157:H7 in 2019, in which both patients were exposed to the same home-processed "jerky" and clinical isolates matched within 2 single nucleotide polymorphisms (SNPs), we discovered, by searching the National Library of Medicine's National Center for Biotechnology Information website, 3 other cases of O157:H7 from 3 Oregon counties-Tillamook, Umatilla, and Douglas-whose clinical isolates were within 9 SNPs of the 2 initial matched cases. We analyzed interview data for 3 case patients and followed up with additional hypothesis-generating questions. Onset of illness for the Tillamook, Umatilla, and Douglas county cases were October 7, 2017, October 27, 2017, and April 30, 2018, respectively. The median age of the 5 case patients was 16 years. Parents of 2 of the 5 case patients, each from a different county, had harvested deer approximately 20 miles from each other in the same Douglas County wildlife hunting unit in late September 2017. The case from Umatilla County was lost to follow-up. Although it is well documented that deer are a viable and substantial reservoir of O157:H7, to our knowledge, this is the first time that venison from a common wildlife hunting unit was found to be associated with a cluster of illnesses. This finding suggests a geographic nidus for O157:H7. We recommend routinely asking about wildlife hunting units when developing exposure hypotheses involving potential venison-associated clusters.