This week’s national wastewater surveillance reveals multiple large and unexpected increases in viral signals, led by an extraordinary surge of Influenza A (pig)—nearly 3,000-fold over baseline—alongside a 12-fold escalation of picornavirus kobuvirus cebes (pig), both detected at the urban site in Columbia, MO. Importantly, these porcine viruses are rarely observed in city environments and their appearance at an urban location, rather than rural, represents a significant deviation warranting further investigation.
Several other urban sites are also experiencing notable viral trends. Human mastadenovirus A showed a more than tenfold increase at Columbia, MO, Greater Boston, MA, and Palo Alto, CA, all urban centers where this virus is typically barely detectable. Likewise, Merkel cell polyomavirus rose sharply (nearly tenfold) in Greater Boston, Palo Alto, and St. Louis, identifying an emerging cluster of activity that bears public health attention. Further, Parechovirus 5 presented with an approximately ninefold increase, notably at both the urban site of Greater Boston, MA and the rural site of Monett, MO, signifying broad geographic activity.
As for nationally monitored priority viruses, Coronavirus SARS-CoV-2 signals are climbing, with a more than threefold increase across Greater Boston, Chicago, and Boise, signaling a moderate upturn in community prevalence. Coronavirus OC43, another respiratory virus, also presents with a noteworthy sixfold rise at Chicago, Riverside, and Boise. Influenza B was detected only at Chicago, and Pneumovirus RSV-A was confined to St. Louis, both without significant increases. Though Influenza A (pig) is typically tied to agriculture, its urban surfacing underscores the need for ongoing clinical vigilance, especially given any existing links between zoonotic viruses and public health.
Several viruses that are usually absent or present at minimal levels are now emerging and should remain under observation. Most prominently, the urban detections of picornavirus kobuvirus cebes (pig) and Merkel cell polyomavirus stand out. Recurring and elevated findings for BK virus, JC virus, and Parechovirus 1B—each up threefold or more at urban and peri-urban sites—may indicate localized outbreaks or increases in susceptible populations.
Given these patterns, communities are advised to maintain heightened hygiene measures, especially in urban areas experiencing atypical viral activity. Public health agencies in affected cities should consider targeted messaging regarding zoonotic risks, reinforcement of immunization schedules for influenza and COVID-19, and vigilance among clinicians for signs of viral illness. If symptoms consistent with these viruses arise, early clinical testing and reporting are encouraged to clarify community risk.
Please note, some site data is delayed: Milan, MO is eight weeks behind, while Ottumwa, IA, Sacramento, CA, and Ontario, CA are one week behind. Interpret patterns at these sites with appropriate caution due to the older data window.