Wastewater Signals May Warn of Whooping Cough Outbreaks Weeks Before Case Reports

Researchers at the University of Osaka and the Osaka Institute of Public Health have shown that monitoring wastewater for pertussis-related DNA can signal an outbreak of the disease, also known as whooping cough, weeks before it shows up in clinical case reports. The study, published in the journal Emerging Microbes & Infections, addresses a gap in conventional surveillance, which depends on people seeking medical care, being tested and being diagnosed before a rise in cases is recognised.

From April 2023 to July 2025, the researchers collected wastewater weekly from four treatment plants across Osaka Prefecture and analysed it for DNA markers associated with Bordetella pertussis, the bacterium that causes pertussis, and the related Bordetella parapertussis. The concentration of a marker called IS481 began rising in 2024, following a pattern similar to reported pertussis cases, but earlier.

In the main analysis, the wastewater signal preceded reported cases by 10 weeks; other analyses showed lead times ranging from 4 to 16 weeks. Because wastewater surveillance does not depend on whether infected people seek medical care or get tested, it can capture broader community-level trends, including mild or asymptomatic infections not reflected in clinical reports.

"By combining wastewater surveillance with clinical surveillance, we hope to detect changes in community transmission earlier," said Dr. Daisuke Motooka of the Research Institute for Microbial Diseases at the University of Osaka. The researchers say the approach could support earlier public health steps such as heightened clinical awareness, expanded testing and infection-prevention measures, shifting from a reactive to a more proactive response to outbreaks.