Development of a wastewater based infectious disease surveillance research system in South Korea

Abstract

Wastewater-based epidemiology has been used in pathogen surveillance for microorganisms at the community level. This study was conducted to determine the occurrence and trends of infectious pathogens in sewage from Yongin city and the relationships between these pathogens and the incidence of infectious diseases in the community. From December 2022 to November 2023, we collected inflow water from six wastewater treatment plants in Yongin city twice a month. The analyzed microorganisms included 15 respiratory viruses, 7 pneumonia-causing bacteria, 19 acute diarrhea-causing pathogens, SARS-CoV-2, Zika virus, hepatitis A virus, poliovirus, Mpox, and measles. They were detected through real-time PCR and conventional PCR. The concentrations of 9 pathogens among them were additionally analyzed using quantitative real time PCR. The correlation was confirmed through statistical analysis with the rate of detection for pathogens reported by the Korea Disease Control and Prevention Agency. Influenza A virus, human adenovirus, and human rhinovirus were moderately correlated (rho values of 0.45 to 0.58). Campylobacter spp. and sapovirus were strong correlated (rho values of 0.62, 0.63). Enteropathogenic E. coli, human coronavirus, and norovirus GII were very strong correlated (rho values of 0.86 to 0.92). We were able to identify the prevalence of respiratory viral infections, pneumonia, and acute diarrhea-causing pathogens in the community through wastewater-based epidemiology data. This study will be helpful in establishing a system for future surveillance of infectious diseases present in sewage.

Keywords: Diarrhea-causing microorganisms; Pneumonia-causing bacteria; Public health; Real-time PCR; Respiratory viruses; Wastewater-based epidemiology.

Figure 1

Correlation between the weekly rate of detection for respiratory viruses from the KDCA and the concentration of viruses detected at the six WWTPs. The rate of detection for each respiratory virus reported weekly by the KDCA and the concentration of each virus detected at the six WWTPs were analyzed and are presented in a graph. The orange bar represents the concentration (copies/µl) of the virus detected in sewage collected twice a month, and the blue line represents the rate of virus detection reported weekly by the KDCA. (A) Influenza A virus, (B) human adenovirus, (C) human coronavirus (229E, NL63, and OC43), (D) human rhinovirus A/B/C, and (E) SARS-CoV-2. For human coronavirus, three subtypes were analyzed (shown in orange for human coronavirus 229E, gray for OC43, and yellow for NL64), and the viral concentrations of human coronavirus represent the sum of the three types. The trend in the concentrations of four respiratory viruses, excluding SARS-CoV-2, was very similar to the trend in the rates of detection reported by the KDCA.

Figure 2

Correlation between the weekly rate of detection for pathogens causing acute diarrheal disease from KDCA and the concentration of pathogens detected in the six WWTPs. The weekly detection rate of each pathogen causing acute diarrheal disease by the KDCA report and the concentration of each pathogen detected in the six WWTPs were analyzed and are presented in a graph. The orange bar represents the concentration (copies/µL) of pathogens detected in sewage collected twice a month, and the blue line represents the rate of pathogen detection reported weekly by the KDCA. (A) Campylobacter spp., (B) enteropathogenic E. coli (eaeA), (C) norovirus GII, and (D) sapovirus. The trend in the concentrations of the four causative agents of acute diarrheal disease detected in sewage was very similar to the trend in the rates of detection reported by the KDCA.

Figure 3

Trends in the rates of detection of pathogens in sewage by season. The graph shows the trend of the rates of detection of each pathogen in sewage by season. For each pathogen, the change in the rate of detection over 3 months is shown. In the case of human coronavirus (229E, NL63, and OC43), human parainfluenza virus 3, and Yersinia enterocolitica, the detection rates tended to decrease as summer approached, while for the detection rate of human rhinovirus A/B/C, Salmonella spp. and Vibrio spp. trended to gradually increase in summer.