Environmental Challenges (Dec 2022)
Pilot study on wastewater surveillance of dengue virus RNA: Lessons, challenges, and implications for future research
Abstract
Dengue virus (DENV) is an enveloped, single-stranded RNA virus that causes approximately 390 million infections, leading to 40,000 deaths annually. Due to the increasing trend of urbanization, water supply scarcity, and climate change, dengue is regarded as the “disease of the future,” requiring robust surveillance for the early detection of DENV infection. Since the virus is shed in urine and saliva and persists in wastewater at different temperatures, our study conducted wastewater surveillance as a novel approach to monitor dengue outbreaks in the Kathmandu Valley, Nepal. The viral concentrates (n = 34), which were previously collected and concentrated from municipal and hospital wastewater, and river water using the electronegative membrane-vortex method, were tested for DENV using quantitative reverse transcription polymerase chain reaction (RT-qPCR) and digital PCR (RT-dPCR). Pepper mild mottle virus, a process control and endogenous biomarker, was detected in all the samples with concentrations ranging from 8.0 to 10.0 log10 copies/L, whereas DENV was not detected in any sample using RT-dPCR and RT-qPCR. The undetected DENV in this study could be attributed to the collection of grab wastewater samples during a low relative prevalence of dengue infection in the region, insufficient sample volume processed, probable viral nucleic acid degradation due to storage of viral concentrate at -25 °C for a long period of time, or inefficiency of the primary concentration method used. This study highlights critical gaps in knowledge and provides recommendations for future implementation of wastewater surveillance of dengue outbreaks, especially in regions where dengue was recently introduced, clinical surveillance is limited, and wastewater surveillance for polio has been adopted.
