Development of a Portable Detection Method for Enteric Viruses from Ambient Air and Its Application to a Wastewater Treatment Plant

Abstract

The ambient air from wastewater treatment plants has been considered as a potential source of pathogenic microorganisms to cause an occupational risk for the workers of the plants. Existing detection methods for enteric viruses from the air using a liquid as the collection medium therefore require special care to handle on-site. Knowledge accumulation on airborne virus risks from wastewater has been hindered by a lack of portable and handy collection methods. Enteric viruses are prevalent at high concentrations in wastewater; thus, the surrounding air may also be a potential source of viral transmission. We developed a portable collection and detection method for enteric viruses from ambient air and applied it to an actual wastewater treatment plant in Japan. Materials of the collection medium and eluting methods were optimized for real-time polymerase chain reaction-based virus quantification. The method uses a 4 L/min active air sampler, which is capable of testing 0.7–1.6 m3 air after 3–7 h sampling with a detection limit of 102 copies/m3 air in the field. Among 16 samples collected at five to seven locations in three sampling trials (November 2007–January 2008), 56% (9/16) samples were positive for norovirus (NV) GII, with the highest concentration of 3.2 × 103 copies/m3 air observed at the sampling point near a grit chamber. Adenoviruses (4/16), NV GI (6/16), FRNA bacteriophages GIII (3/16), and enteroviruses (3/16) were also detected but at lower concentrations. The virus concentration in the air was associated with that of the wastewater at each process. The results imply that the air from the sewer pipes or treatment process is contaminated by enteric viruses and thus special attention is needed to avoid accidental ingestion of viruses via air.

COVID-19 infection risk from exposure to aerosols of wastewater treatment plants

“…In another study, 56% (9/16) of air samples from a WWTP in Japan were positive for norovirus (NV) GII. Adenoviruses (4/16), NV GI (6/16), FRNA bacteriophages GIII (3/16), and enteroviruses (3/16) were also detected, but at lower frequencies ( Matsubara and Katayama, 2019 ).…”

Aerosol Transmission of Norovirus

“…The different results may be related to different air samplers, and different sampling mechanisms may affect the active state of viruses in aerosols. At present, there is still a lack of mature in vitro culture systems for NoV [ 33 ], and there is no gold standard method or instrument for sampling NoV aerosol [ 35 ]. Therefore, the infectivity research of NoV aerosols has been hampered.…”

“…In addition, Matsubara et al [ 35 ] developed a portable collection method (HA vortex method) for various enteric viruses (including NoV) in the air, and used a mixed cellulose membrane (HA 0.45 µm, Millipore, Billerica, MA, USA) as the collection medium and eluted the viruses using a glycine buffer. Its collection capability was similar to the liquid medium collection method (Biosampler, SKC) and had been successfully applied to detect enteric viruses at a sewage treatment plant in Japan.…”

Bioaerosols in Wastewater Treatment Plants: Trends, Recent Advances, and the Influence of SARS-CoV-2 Outbreak

“…Presently, two primary techniques are employed: the conventional culture-based method utilizing nutrient media for microbial cultivation and the non-culture-based method relying on DNA-based techniques. Several non-culture-based techniques were used in the literature, including polymerase chain reaction (PCR) [24,25], quantitative or real-time polymerase chain reaction [2,14,[26][27][28], and fluorescence in situ hybridization [29].…”