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

Fecal shedding of SARS-CoV-2 from COVID-19 patients and presence of the viral RNA in wastewater have extensively been reported. Some wastewater treatment plant (WWTP) processes generate aerosols which have the potential to transmit pathogenic microorganisms and present a health risk for exposed individuals. We analyzed the presence of viral RNA of SARS-CoV-2 in raw wastewater and air samples of WWTPs. The risk that may arise from exposure to virus-contaminated aerosols of wastewater was estimated by developing a quantitative microbial risk analysis (QMRA) method. SARS-CoV-2 was detected in 9 of 24 (37.5%) wastewater samples with a concentration about 104 genomic copies L-1. The viral RNA was also detected in 40% (6/15) of air samples. QMRA analysis showed a relatively high risk of SARS-CoV-2 infection for wastewater workers via exposure to the viral aerosols. The estimated annual infection risk ranged from 1.1 × 10-2 to 2.3 × 10-2 per person per year (PPPY) for wastewater workers which was higher than the reference level recommended by WHO (10-3 pppy). However, due to the lack of data on survival of SARS-CoV-2 in wastewater and its fate in aerosolized state, more research is needed to determine the importance of wastewater in transmission of COVID-19.

The Black Flies (Diptera: Simuliidae) of Iran.

Although Iran has a large geographic area encompassing 13 ecoregions, its simuliid fauna remains largely unexplored. To begin redressing this faunal gap, we reviewed literature records and coupled morphological and chromosomal identifications of material newly collected from 16 sites in Iran. Twenty-three nominal species are now recognized, including new country records for Simulium crassicaulum (Rubtsov) and Simulium alajense Rubtsov, and the southernmost world record for Simulium transcaspicum Enderlein. Multiple cytoforms of the Simulium aureum group, Simulium bezzii complex, and Simulium ornatum group were found.