Wastewater and Clinical Based Epidemiology for Viral Surveillance in the Nile Delta of Egypt

The release of inadequately treated wastewater, containing human viruses, into the water environment or agricultural use represent a major problem in public health. In this study, SYBR Green-based real-time polymerase chain (qPCR) was applied to evaluate the prevalence of human polyomavirus (HPyV), papillomavirus (HPV), hepatitis A virus (HAV), and hepatitis E virus (HEV) in urban sewage and among children with acute gastroenteritis. The seasonal distribution in wastewater and viral removal by wastewater treatment process were also evaluated, over the 2 year sampling period. HPyV, HPV, HAV, and HEV were detected in 68%, 39.6% 42.4%, and 33.3% of the raw sewage, respectively, with highest incidence in winter season. In treated sewage samples, HPyV, HPV, HAV, and HEV were detected in 21%, 9.4%, 18.7%, and 0%, respectively. Furthermore, among the 200 diarrheal stool samples, HPyV, HPV, HAV, and HEV were detected in 72.5%, 50%, 13%, and 5%, respectively. HPyV was more prevalent in both environmental and clinical samples. The mean concentration of these viruses in raw sewage, treated sewage, and stool samples was 3.62 × 10⁶ GC/ml, 4.03 × 10³ GC/ml, and 4.05 × 10⁶ GC/g, respectively. Examination of wastewater treatment process efficiency based on mean concentration values at entry and exit observed an overall reduction of 49.5%, 47.9%, 41.2%, 100%, for HPyV, HPV, HAV, and HEV, respectively. This study showed the benefit of environmental monitoring as an additional tool to investigate the epidemiology of these viruses circulating in a given community.