Human Adenovirus Detection and Genetic Characterization in Irrigation Water from the Riyadh Region, Saudi Arabia

Adenoviruses are considered one of the most persistent enteric pathogens that can penetrate entire aquifer matrices. An ongoing monitoring of irrigation water is essential to mitigate potential public health risks. We investigated the prevalence of human adenoviruses (HAdV) in the groundwater discharge basins of Aluraiji (AW-DB) and Diriyah (DW-DB) and in the irrigation water of Al Harriq (H-IW) and Al Hayer (AH-IW) from January to December 2021. The meteorological impact (temperature, relative humidity, and wind speed) on HAdV prevalence and molecular diversity was investigated by targeting a selected region of the Hexon gene. The samples were concentrated using the polyethylene glycol precipitation (PEG) method. HAdVs were detected using PCR and sequenced by Sanger sequencing, and phylogenetic analysis was performed. The highest HAdV prevalence was recorded in H-IW, AH-IW, and DW-DB (100%). HAdV sequences were found to be closely related to species F (type 41) with a predominance of the 00-2B64 sequence (86.4%). Phylogenetic analysis depicted a close relationship of this study's isolate 00-2B64 to a Brazilian and Saudi isolate, whereas 08-2B64 was found to be related to a sequence from an AnNazim landfill (LF1; d = 0.00) from Riyadh, Saudi Arabia. A high HAdV prevalence was recorded at a temperature range of 19-28 degrees C, wind speed was recorded at a range of (16-20 km/h), and relative humidity was recorded at a range of (15-25%). Meteorological variations exhibited no significant effect on the prevalence of HAdVs. The findings provided data on HAdV prevalence and predominant species in the irrigation water of Riyadh, Saudi Arabia and presented information regarding the environmental effects of HAdV persistence. In public health contexts, this will help in the planning of disease control strategies.