Study finds cancer-causing viruses emerging from wastewater

For the first time, researchers have managed to detect and track in wastewater all the main viruses associated with the development of tumours. A discovery that could open up new prospects for prevention, health surveillance and monitoring of oncogenic infections in the population.

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The study, coordinated by Anthony Maresso and Justin Clark of the Baylor College of Medicine and published in the journal Applied and Environmental Microbiology, was carried out in collaboration with the University of Texas Health Science Center at Houston.

The researchers analysed wastewater samples collected between May 2022 and May 2025 at more than 40 sites across 16 cities in Texas, covering around a quarter of the state’s population. For the analysis they used an advanced genetic sequencing technology known as “hybrid-capture”, capable of identifying simultaneously more than 3,000 known human viruses and new possible mutations through a single test.

According to the authors of the study, oncogenic viruses may be responsible for around one in five cancers worldwide. Among the best known are human papillomavirus (HPV), associated with cervical and throat cancers, and hepatitis B and C viruses, linked to liver carcinoma.

“Oncogenic viruses can cause around one in five cancers globally,” explained Anthony Maresso, professor of molecular virology and microbiology. “Since these infections often remain asymptomatic for years or even decades, many people do not realise they are infected until the tumour develops. This makes it very difficult to implement early preventive interventions.”

The analysis of wastewater detected all the main oncogenic viruses known to date, including HPV, hepatitis B and C viruses, cancer-associated polyomaviruses, Epstein-Barr virus and the herpesvirus linked to Kaposi’s sarcoma.

The researchers also observed a significant increase in the presence of several oncogenic viruses over the three years of monitoring. In particular, HPV, Epstein-Barr virus and some polyomaviruses showed marked rises after 2024.

According to the team, the causes of this increase are not yet clear, but could be related to the resumption of travel, more frequent interpersonal contact and the end of the distancing measures introduced during the Covid-19 pandemic.

Particular attention was paid to human papillomavirus. “There are hundreds of HPV types, but only some are considered to be high oncogenic risk,” explained Justin Clark. “HPV-16 and HPV-18 together cause more than 70% of cervical cancers worldwide.”

The study showed that low-risk HPV variants were more widespread, but high-risk variants also recorded a significant increase between late 2024 and early 2025. HPV-16 was consistently more common than HPV-18, in line with previous international clinical studies.

Another important finding concerns the Gardasil 9 vaccine: all nine HPV types targeted by the jab were detected in wastewater. According to the authors, this could in future allow environmental monitoring to be used to assess the effectiveness of vaccination campaigns in the real population.

“Our study shows that tumour-associated viruses can be monitored through wastewater,” Maresso concluded. “This opens up new opportunities to better understand the relationship between these viruses and the human population and to develop more effective public health strategies.”