This study examined the presence and seasonal variations of human oncogeneic viruses and also enteric hepatitis viruses in raw sewage, influent, and clinical samples. The study also evaluated the degree of elimination of these viruses over two years of investigation. Our research uncovered that the current wastewater treatment methods are inadequate in eliminating these viruses, since we identified the presence of these viruses in samples obtained from sewage, intake, and sewage. The main sources of these viruses are the infected individuals' blood, urine and/or feces. Extended excreta of these viruses in urine and feaces, which is then released into wastewater, poses serious environmental risks and may serve as a vehicle for the spread of viruses to other peoples due to resistance of these viruses to wastewater treatment procedures. The results of our study align with previously published data that demonstrate the durability and resilience of these viruses to various environmental conditions in different bodies of water. Later, it was discovered that these viruses were present in the urban sewage of several other countries, including South America (Comerlato et al., 2016, Castro et al., 2023), Pakistan (Ijaz et al., 2023), Italy (Iaconelli et al., 2015), and Australia (Ahmed et al., 2010). Castro et al., 2023 found high prevalence for HAV and HEV as following 61.1% of clinical samples and 39% of sewage samples had HAV. 15.9% of clinical samples and 22.5% of sewage samples had HEV identified; this high prevalence may be due to high number of tourists and immigrants in the city. In contrast La Rosa et al., 2014 found a low prevalence for HAV during two year of survey where a total of 38/157 wastewater samples (24.2%) were positive for HAV and these results are corresponded to Italy's designation as a low- to intermediate-endemic nation. Even with preventive efforts including better sanitation, water supply, and the HAV National Vaccination Programme, the presence of HEV and HAV in clinical samples and sewage supports the notion that the virus is still circulating in Egypt
Our HPyV results was in accordance with Kokkinos et al., 2011 where they found that PyVs were detected in 68.8% (33/48), of the samples collected from untreated urban sewage (plant's inlet) from Greece. Hamza and Hamza, 2018 found high prevalence about 73% for HPyV in wastewater samples. There was a little difference in detection rate of HPyVs obtained by Macena et al., (2021) where they detected high percentage with 90% of JC Polyomaviruses in wastewater samples at Brazil and this could be as a result of the small number of samples that were collected which limits the study results. High prevalence HPyV in stool samples are remarkable during the current study in contrary the other study done by Yu et al., (2012) where they found only 56% in Diarrhea samples. There could be a number of reasons for this variation in results, including variations in the sample type, primer sets, and geographic location.
Hamza and Hamza, (2018) detected HPVs in 30.5% of wastewater samples which considered slightly lower than our results. The percentage of HPV either in sewage or stool samples (40% and 50%) were slightly higher than in our previous study (Ahmed et al., 2019) where HPVs were the detected rate in sewage and stool samples was 24.4% and 28.3%, respectively. Di Bonito et al., 2015 found low prevalence rate for HPVs with 12.5% are detected in human stool samples this low detection rate may be due to sample size where very little sample material was collected for the investigation also the sensitivity of the molecular assays used during this study might have been lowered by partial inhibitor removal.
Future post-treatment water virological controls are crucial, as demonstrated by environmental monitoring of these viruses. HAV and HEV were detected in sewage in all seasons, demonstrating the circulation of these viruses over time. Higher HAV detection was found during the winter while HEV was observed more frequently in summer.
The findings also showcased the capacity of these viruses to serve as markers of water source contamination (Hundesa et al., 2006; Hamza et al., 2009, Ahmed et al., 2019). Many viruses, harmful bacteria, helminth eggs, protozoan cysts, and other microorganisms can be found in human faeces, and human excreta is linked to a number of serious infectious diseases
Based on Rusin et al. (2000), the majority of enteric viruses result in non-apparent infection. The release of these viruses in feces, urine, and respiratory secretions can occur at any time during infection highest concentration in feces and with the lowest infective dose (Toze, 1997 and 1999) causing acute gastroenteritis which is one of the viral infections that affects the population the most. A number of variables, including the infectious dosage, the infectious agent's pathogenicity (the ability of virus to infect and harm the host), and host and environmental conditions, influence how the disease develops. The incubation period, which varies according on the virus, is the interval of time between infection and the onset of clinical symptoms (Bitton et al., 1997).
Wastewater is a promising method for tracking the epidemiology of enteric viruses circulating in the population, as evidenced by the scientific literature. This is because wastewater samples can be used to identify, quantify, and concentrate the genetic material of these viruses. In addition, analyzing the genetic material of these enteric viruses present in wastewater allows us to partly monitor asymptomatic and pre-symptomatic cases that have appeared in the community, thereby can help create and manage prevention and control measures through mitigation medical surveillance agency to control epidemic pathogens in a certain location (Ázara et al., 2023).
Furthermore, various infectious diseases caused by microorganisms found in wastewater can also be monitored by the WBE. The extension and enhancement of fundamental urban sanitation practices would, therefore, immediately contribute to the diagnosis of people's health. This study addressed the presence of enteric hepatitis and enteric oncogenic viruses in sewage and the removal of these pathogens in WWTPs, as well as concentration and detection/quantification methods viral in this type of sample Conventional treatment processes in wastewater systems have low effectiveness in removing disease-causing organisms, because traditional wastewater treatment plants are not specifically designed for this purpose (Bhatt et al., 2020). Otherwise of virus adsorption to sediment appears greatly prolong the infectivity of viruses (Reynolds and Pepper, 2000). Viral pathogen discovery in treated effluent, as reported in a number of places worldwide (Baggi et al., 2001; Enriquez et al., 1995; Van Berg et al., 2005; Ueki et al., 2005), is a sign that the methods currently in use are ineffective. In addition to enteric viruses, raw sewage contains bacteria from all phylogenetic domains as well as other types of viruses (Haji Ali et al., 2021, Ázara et al., 2023).
This study has some limitations such as the genotyping for the detected viruses where is too much important to know the strains that are common in the studied geographical area.