Quantitative Assessment of Microbial Pathogens and Indicators of Wastewater Treatment Performance for Safe and Sustainable Water Reuse in India

Environmental Surveillance and Detection of Infectious Highly Pathogenic Avian Influenza Virus in Iowa Wetlands

Avian influenza viruses (AIVs) infect both wild birds and domestic poultry, resulting in economically costly outbreaks that have the potential to impact public health. Currently, a knowledge gap exists regarding the detection of infectious AIVs in the aquatic environment. In response to the 2021-2022 Eurasian strain highly pathogenic avian influenza (HPAI) A/goose/Guangdong/1/1996 clade 2.3.4.4 lineage H5 outbreak, an AIV environmental outbreak response study was conducted using a One Health approach. An optimized method was used to temporally sample (April and May 2022) and analyze (culture and molecular methods) surface water from five water bodies (four wetlands and one lake used as a comparison location) in areas near confirmed HPAI detections in wild bird or poultry operations. Avian influenza viruses were isolated from water samples collected in April from all four wetlands (not from the comparison lake sample); HPAI H5N1 was isolated from one wetland. No virus was isolated from the May samples. Several factors, including increased water temperatures, precipitation, biotic and abiotic factors, and absence of AIV-contaminated fecal material due to fewer waterfowl present, may have contributed to the lack of virus isolation from May samples. Results demonstrate surface water as a plausible medium for transmission of AIVs, including the HPAI virus.

Wastewater-based epidemiology of Campylobacter spp.: A systematic review and meta-analysis of influent, effluent, and removal of wastewater treatment plants

Campylobacter spp. is one of the four leading causes of diarrhoeal diseases worldwide, which are generally mild but can be fatal in children, the elderly, and immunosuppressed persons. The existing disease surveillance for Campylobacter infections is usually based on untimely clinical reports. Wastewater surveillance or wastewater-based epidemiology (WBE) has been developed for the early warning of disease outbreaks and the detection of the emerging new variants of human pathogens, especially after the global pandemic of COVID-19. However, the WBE monitoring of Campylobacter infections in communities is rare due to a few large data gaps. This study is a meta-analysis and systematic review of the prevalence of Campylobacter spp. in various wastewater samples, primarily the influent of wastewater treatment plants. The results showed that the overall prevalence of Campylobacter spp. was 53.26 % in influent wastewater and 52.97 % in all types of wastewater samples. The mean concentration in the influent was 3.31 ± 0.39 log10 gene copies or most probable number (MPN) per 100 mL. The detection method combining culture and PCR yielded the highest positive rate of 90.86 %, while RT-qPCR and qPCR were the two most frequently used quantification methods. In addition, the Campylobacter concentration in influent wastewater showed a seasonal fluctuation, with the highest concentration in the autumn at 3.46 ± 0.41 log10 gene copies or MPN per 100 mL. Based on the isolates of all positive samples, Campylobacter jejuni (62.34 %) was identified as the most prevalent species in wastewater, followed by Campylobacter coli (30.85 %) and Campylobacter lari (4.4 %). These findings provided significant data to further develop and optimize the wastewater surveillance of Campylobacter spp. infections. In addition, large data gaps were found in the decay of Campylobacter spp. in wastewater, indicating insufficient research on the persistence of Campylobacter spp. in wastewater.

Treatment of clinical laboratory sewage using a decentralized treatment unit and risk reduction for its reuse in irrigation using hybrid disinfection

The disinfection efficacy of standalone chlorine, UV and their combined approach (hybrid) was investigated for the coliform removal in BioKube 1 and 2 treated effluents collected from different environmental settings of clinical and domestic wastes. Chlorine and UV disinfection were applied to BioKube treated wastewater with doses from 0 to 4 mg L-1 and 0-166 mJ cm-2 respectively. Combined disinfection strategies were designed to reduce the dose of chlorine and UV and to exploit the synergistic effect of them. The culturable coliforms were enumerated in treated wastewater sample (control), immediately after (reduction), and 24 h post disinfections (regrowth) using culture media plating and colilert-18 media. Both the BioKube systems (1 and 2) were effective in achieving the strict norms of physicochemical parameters, but not following the coliform counts of treated effluent for reuse in irrigation. A hybrid strategy of chlorine followed by UV was found to be the most effective among various standalone and combination approaches for the removal of coliforms (>4 log ER or <1000 CFU/100 mL) from both the treated effluents. However, coliform present in treated effluent of BioKube 1 were resisting (regrowth) against all kind of applied disinfectants except chlorine followed by UV dose at or more than 0.5 mg L-1 + 41 mJ cm-2. Limited reports are available on hybrid disinfection approaches with decentralized packaged sewage treatment units and this study would help to adopt as an effective tertiary treatment strategy for reuse of treated sewage for irrigation while ensuring public health safety.