Sporadic detection of dengue virus RNA in California wastewater solids

DENV RNA was detected in 1.2% of 1,072 untreated California wastewater samples (13/1,072) from five treatment plants, with only southern California showing positives.

• Why it matters: Detection rates vary by setting and method, and it is unclear whether wastewater-based surveillance adds value for dengue monitoring in low-incidence regions like California.
• What they did: The study analyzed 1,072 wastewater samples collected December 2023–December 2025 and compared DENV RNA results with weekly clinical incidence and Aedes aegypti abundance from the California Department of Public Health.
• The result: DENV-1 (0.6%, 6/1,072) and DENV-2 (0.4%, 4/1,072) were most common, with no DENV-3 detected; wastewater DENV RNA frequency increased with higher incidence, but weekly RNA levels were not correlated with incidence.