Wastewater-based surveillance (WWBS) is one of the most promising alternatives to clinical surveillance for human viral pathogens and has gained momentum in several Global North countries as a consequence of the contraction of the worldwide monitoring effort during the COVID-19. Even though relevant WWBS studies were set during 2020 to monitor its infectious agent, the SARS-CoV-2 virus, no major coordinated effort has been yet established in Mexico for these techniques.

Regular clinical studies require patients to search for health assistance, which is normally a reflect of them developing symptoms of a disease. However, for some infectious diseases, even asymptomatic patients can transmit disease without even noticing themselves. Likewise, Public Health actions are normally defined after an outbreak is already well under way.

To cope with this, WWBS studios the incidence of water-borne pathogens excreted from a human population as a whole, not patient by patient based on drainage contents. This alternative enables an early detection of even low-prevalence pathogens based on their’ genetic materials present in wastewater.

Their past experience in genomic an epidemiological surveillance as CoViGen-Mex allowed Dr. Rodrigo García López’s group at the Wastewater Epidemiology and Metagenomics Laboratory (WEML) of the Institute of Biotechnology of UNAM in Cuernavaca, to carry out a pilot study aimed at deploying WWBS in Mexican wastewater treatment plants to thoroughly assess pathogenic viruses and bacteria, with a special focus on determining the complete spectrum of host-specific agents that might be relevant for the Public Health under a novel One-Health focus.

The main objective consists of monitoring periodic fluctuation of relevant viral respiratory and gastrointestinal pathogens in wastewater, determining the levels of infectious agents during epidemiological surges through epidemiological and molecular biology approaches, and to broaden the analyses to study the whole viral diversity through viral metagenomics, enabling the exploration of their functional profiles.

This is a prospective multi-omic epidemiological study. Wastewater composite samples are actively been collected every two weeks during one year in a Mexican treatment plant following evaluation of water quality and virus concentration. Extracted RNA/DNA is used out to carry out two types of analyses: targeted amplification with RT-qPCR to monitor different pathogens, selected based on traceability, and metagenomes, will are obtained with shotgun high-throughput sequencing methods.

Through collaborations with Dr. Luz Bretón Deval from SECIHTI’s Researchers for Mexico, the scope has been extended to add a context of water contamination, by setting up physicochemical analyses and complementary bacterial sequencing aimed at the detection of antibiotic resistence genes (ARGs), that historically have been subject of horizontal gene transfers mediated by bacteriophage action, viruses infecting bacteria.

The current study will help establish a comprehensive set of WWBS applications that can be used in Mexico to broaden the scope of surveillance protocols to include multiple viral pathogens and the detection of non-standard agents having epidemic potential and ARGs in an effort to promote future pandemics.