Wastewater and clinical based epidemiology for viral surveillance in urban sewage and clinical samples from Egypt

Abstract

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 we evaluated the presence of polyomavirus (HPyV), papillomavirus (HPV), hepatitis A virus (HAV), and hepatitis E virus (HEV) in urban sewage and among children with acute gastroenteritis by real time PCR. The seasonal distribution in wastewater and viral removal by wastewater treatment process were also evaluated. HPyV, HPV, HAV, and HEV, were detected in 68%, 39.6% 42.4%, and 33.3% of the raw sewage and in 21%, 9.4%, 18.7%, and 0% of the treated sewage samples. Among the 200 children with acute gastroenteritis, HPyV, HPV, HAV, and HEV were detected in 72.5%, 50%, 13%, and 5% of stool samples tested, respectively. HPyV was more prevalent in both environmental and clinical samples. The concentration of these viruses (HPyV, HPV, HAV, HEV) in raw sewage, treated sewage, and stool samples ranged from 1.30×10¹ GC/ml to 9.86×10⁷ GC/ml with a mean concentration of 3.62 ×10⁶, from 0 GC/ml and 2.15×10⁵ GC/ml with a mean concentration of 4.03×10³, and from 1.40×10¹ to 9.85×10⁷ GC/g with a mean concentration of 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.