ABUNDANCE OF HUMAN RESPIRATORY VIRUSES IN SEWAGE DURING TWO CONSECUTIVE AGRICULTURE SEASONS IN YUMA, ARIZONA

Abstract

Yuma, Arizona, is an indispensable cornerstone of U.S. agriculture, producing ~90% of North America’s leafy greens during the winter months. The objective of this study was to assess the occurrence of human respiratory viruses and their relative abundance in sewage across two Yuma communities during the agricultural season. Raw sewage samples from two local municipal treatment plants were collected and concentrated between November and February during two successive growing seasons (2022-2023 and 2023-2024). Viral RNA was then extracted and sequenced using Illumina’s high throughput metagenomic sequencing technology coupled with digital PCR amplification to identify human respiratory viruses. The principal findings of this study indicate that during peak agricultural seasons (November through February annually) in Yuma County, Arizona, viral richness and concentrations were typically higher compared to pre- (July and September annually) and post-season (April and June annually). Increased detection of SARS-CoV-2, influenza A, influenza B, and respiratory syncytial virus (RSV) during peak-agricultural seasons may suggest seasonal infection trends in the community. The 2023-2024 growing season was characterized by increased viral richness compared to 2022-2023, which may be due to the easing of COVID-19 restrictions as well as environmental factors including temperature. Overall, this study demonstrates the importance of wastewater surveillance in characterizing the respiratory disease trends of agriculturally significant regions in the U.S. to safeguard the health of seasonal workers and local communities alike.