Risk Assessment of an Illegal Laboratory in Reedley, California, Using Geospatial Analysis of Open‐Source Epidemic Intelligence Data

ABSTRACT

An illegal laboratory discovered in Reedley, California, in December 2022 was in a warehouse, operating without a license, handling about a thousand transgenic mice, chemicals, and possibly over 20 pathogens, including vials labeled Ebola, which were never tested but destroyed. This study aimed to estimate epidemic signals around the Reedley illegal laboratory using open‐source epidemic intelligence data. We utilized data from EPIWATCH, from October 2021 to October 2023, a year prior to and a year after the establishment of the illegal laboratory. The spatial pattern of outbreak signals was analyzed using hotspot analysis, and the distances of outbreak signals from the laboratory were measured. In California, an upward trend in outbreak signals of pathogens associated with the laboratory was noted in December 2022, April 2023, and August 2023. In the hotspot analysis, California and eight other states in the United States (US) were identified as hotspots. Narrative evidence revealed the presence of a sick employee working in the laboratory, whose child also became ill. Changes in disease patterns reported in California or the US in the year following the establishment of the illegal laboratory may or may not be linked to the illegal laboratory. A subsequent illegal lab linked to Reedley was identified in Las Vegas in 2026, highlighting the ongoing threat to biosecurity. EPIWATCH geospatial and temporal analysis can enhance the public health risk assessment of threats associated with illegal laboratories, especially when there is no available testing or reporting.