Sewage monitoring detects pertussis outbreaks 10 weeks earlier than clinical reports

Whooping cough moves through communities in waves, but by the time doctors recognize an outbreak, the disease has already taken hold. Pertussis—the bacterial infection that causes the violent, distinctive cough—remains a periodic threat worldwide, and for infants too young to complete their vaccination series, it can be life-threatening. The problem is structural: outbreaks are detected only after people get sick enough to seek medical care, get tested, receive a diagnosis, and that diagnosis gets reported to health authorities. Each step takes time. Each step creates a gap.

Researchers at the University of Osaka and the Osaka Institute of Public Health have found a way to see the outbreak coming before it arrives in the clinic. By monitoring sewage, they detected the bacterial signatures of pertussis weeks before a single case appeared in official reports. The discovery suggests a fundamental shift in how public health systems could respond to infectious disease—not waiting for people to fall ill, but watching the community's waste stream for early signs of trouble.

Between April 2023 and July 2025, the team collected wastewater samples weekly from four treatment plants across Osaka Prefecture. They tested the sewage for DNA markers associated with Bordetella pertussis and Bordetella parapertussis, the bacteria responsible for whooping cough and a related illness. What they found was striking: the concentration of a specific pertussis marker called IS481 began climbing in 2024, and its rise followed the same temporal pattern as the officially reported cases—but it arrived first. In their main analysis, the wastewater signal led clinical reports by ten weeks. Other statistical approaches showed lead times ranging from four to sixteen weeks, all pointing in the same direction: the sewage was telling the story before the hospitals were.

The advantage of this approach is profound. Wastewater surveillance captures what clinical surveillance cannot. It does not depend on whether infected people feel sick enough to see a doctor, whether they can access testing, or whether they report their illness. It catches the mild cases and the asymptomatic infections—people who shed the bacteria but never enter the medical system. It reflects the true burden of disease moving through a community, not just the fraction that surfaces in a doctor's office.

Dr. Daisuke Motooka of the Research Institute for Microbial Diseases at the University of Osaka framed the vision plainly: by combining wastewater surveillance with traditional clinical tracking, public health systems could detect shifts in community transmission much earlier. That early signal would allow for heightened clinical awareness among doctors, expanded testing capacity, and infection-prevention measures—all deployed before an outbreak reaches its peak. It represents a shift from reaction to anticipation, from managing a crisis after it has begun to preparing for one you can see coming.

The implications extend beyond Osaka. If wastewater monitoring can reliably forecast pertussis outbreaks, the same approach might work for other infectious diseases. Public health agencies could move from a posture of response—waiting for cases to accumulate, then scrambling to contain them—to one of preparedness. They could warn clinicians to watch for symptoms, stock testing supplies, and implement precautions before the surge arrives. For infants and other vulnerable populations, those extra weeks of warning could mean the difference between an outbreak that is contained and one that spreads unchecked. The sewage system, it turns out, has been telling us what we needed to know all along.