الفهرس 
Review of LiteratureOnly 14 pages are availabe for public view
 |  | from | 155 |  |  |
| | | from | 155 | | |
Abstract
There are hundreds of viruses that infect humans and most are released into feces and urine making their way into the environment by excretion or secretion of bodily fluids or skin cells in high numbers.
Despite the lack of data on the efficiency of HPVs and HPyVs removal during wastewater treatments, numerous studies on oncogenic viruses clearly indicate that treatment procedures cannot completely eliminate viruses present in wastewater, with the consequent discharge of infectious viral pathogens into water environments that increase the possibility of these viruses to be transmitted by the waterborne route. The observed abundance and wide dissemination of HPVs and HPyVs strongly suggest the need to evaluate potential health risks associated with this viral contamination of the environment. The discharge of treated civil wastewater into natural waters or their reuse in industry and agriculture involves virological risks for the exposed population. So, a better understanding of viral contamination and resistance to treatments is needed to assess and control such risks.
In the present study, ninety wastewater samples were collected monthly during October 2014 to October 2017 from Zenin wastewater treatment plant. There were 30 activated sludge samples and 60 wastewater samples represented as 30 samples from raw wastewater (inlet), and 30 samples from treated effluent (outlet). Also, sixty stool samples from patients that suffering from tumor cancer were kindly supplied from the National Cancer Institute in Giza.
The incidence of HPVs and HPyVs in total collected samples was detected by using nested and semi-nested PCR techniques and real-time PCR for HPyVs. DNA sequencing was carried out to positive samples and compared with the internationally detected and reported in the gen bank. Also, the presence of inhibitors in our samples was tested by using human Adenovirus type 2 that spiked in some raw wastewater and activated sludge samples. The obtained results summarized in the following points:
A. The incidence of HPVs in wastewater using MY09/MY11 primer was 12.2 % (11/90) in total collected samples. The percentage HPVs in activated sludge was 6.6% (2/30) while it reached to 23.3% (7/30) and 6.6% (2/30) in raw wastewater (inlet) and treated effluent (outlet), respectively. In 2nd round using GP5+/GP6+ primer, the percentage of HPV was 24.4% (22/90) in total collected samples where it was 26.7% (8/30) in sludge while in wastewater was 23.3% (14/60) represented as 33.3% (10/30) in raw wastewater (inlet) and 13.33% (4/30) in treated effluent wastewater (outlet).
B. In stool specimens the percentage of HPV reached to 28.3 % (17/60) among hospitalized patients that suffering from cancer tumors and gastroenteritis. The incidence of HPV in females was higher than males, as it was 64.7% (11/17) and 35.3% (6/17), respectively. The results of the present study showed that HPV16 genotype was circulating in Egyptian environment in the period from 2014 to 2017.
C. The incidence of HPyV in wastewater was 78.9% (71/90) divided as 100% (30/30) in sewage sludge, 83.3% (25/30) and 53.3% (16/30) in raw wastewater and treated effluent, respectively. For JC and BK 60% (18/30) and 40% (12/30) were positive in activated sludge samples, respectively. While in wastewater samples the percentages were 56% (14/25) and 44% (11/25) in raw wastewater and 56.3% (9/16) and 43.8% (7/16) in treatment effluents for JC and BK of Zenin wastewater treatment plant, respectively.
D. In stool specimens the percentage of HPyVs DNA was 58.3% (35/60) among hospitalized patients suffering from cancer tumors divided as 54.3% (19/35) and 45.7% (16/35) for BKV and JCV, respectively in total collected stool specimens. The percentage of HPyV was higher in female than males.
E. The median viral load of HPyVs was 3.5x103 to 4.02x104 GC/L.in activated sludge samples. But it was 6.02x104 to 5.3x104 GC/L and 6.85x103 to 6.2x103 in raw wastewater and in treated effluent samples, respectively. In stool specimens, its range was found to be between 2.5x105 and 1.24x107 GC/L.
F. Seasonal variation of HPyVs indicated that these viruses were resistant to the most environmental conditions as they were detected in all seasons of the year.
Generally, the obtained results indicated that HPVs and HPyVs were detected in clinical stool specimens, raw wastewater and treated effluent, this reflect that wastewater may still contain human viruses after treatment process, and their reuse in agriculture, industry or their discharge into Nile river water and the water used for recreational purposes can therefore expose people to viral infection and health hazard impact. It would therefore appear advisable to add virological monitoring to the routine testing performed for wastewater plant management. On the other hand, the obtained data showed a constant presence of HPyV that could be considered as the best indicator to evaluate the efficacy treatment of wastewater plants in eliminating viruses. Furthermore, the levels of viral contamination observed in the effluent should induce precautions for its reuse.