Wastewater Surveillance for Xylazine in Kentucky

IntroductionIn the United States, xylazine, the veterinary sedative, has emerged as a major threat to people who use illicitly manufactured fentanyl and other drugs. To compare wastewater detection of xylazine with other public health and safety surveillance data from 2019 to 2023 in Kentucky.Materials and MethodsWastewater samples from five rest areas, two truck weigh stations and four wastewater treatment plants (WWTPs) were tested for xylazine. Wastewater xylazine positivity rates were compared to xylazine-positive submission rates from the National Forensic Laboratory Information System (NFLIS) and Kentucky's fatal overdoses in 6-month periods (period 1=January-June; period 2=July-December).ResultsXylazine was detected in 61.6% (424/688) of daily wastewater samples from roadway sites/WWTPs. For roadways, detection increased from 55% (period 1 2021) to 94% (period 1 2023), and WWTPs had an overall detection of 25.8% (n=66 samples, period1/2 2022). Increasing roadway positivity corresponded to trends in NFLIS xylazine positive submission rates: 0.19 per 1,000 submissions (period 1 2019) to 2.9 per 1,000 (period 2 2022, latest available). No deaths from xylazine were reported publicly in Kentucky though we identified one to four (true count suppressed) deaths in the overdose surveillance system which, in back-of-the envelope comparisons with other states, is far fewer than expected.ConclusionsWastewater signals indicate broad geographic exposure to xylazine in Kentucky, yet health outcomes data suggest otherwise. Our findings may inform regional, national and international efforts to incorporate wastewater-based drug surveillance. Harm reduction activities along roadways may be needed and suitable locations.