الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 215 |  |  |
| | | from | 215 | | |
Abstract
Enteric viruses are excreted with human feces and have been found not only in waste water but also in rivers, recreational water and seawater as well as in ground water and even treated drinking water. In the USA, 10% of water borne outbreaks are reportedly associated with viral agents. Among the diseases caused by enteric viruses are epidemic gastroenteritis, meningitis, myocarditis and hepatitis. Some RNA viruses, like rotavirus, sapovirus, astrovirus, enterovirus, hepatitis A virus and hepatitis E virus, are capable of causing waterborne epidemics of gastroenteritis. Furthermore, dsDNA virus, human adenovirus (HAdV) especially serotypes 40 and 41 are involved in the etiology of outbreaks. Human enteric viruses are non-enveloped and highly stable which means that they can survive well in the environment
The aim of the present study is to compare between human adenoviruses and rotaviruses to choose the most suitable candidate to serve as a viral indicator of human viral contamination in the Egyptian aquatic environment.
Water samples, sewage samples and clinical samples were tested for rotaviruses and adenoviruses using RT-PCR followed by nested RT-PCR and by PCR followed by nested PCR then by gel electrophoresis respectively. The positive samples were further investigated by real time PCR to detect the number of human adenovirus and rotaviruses geno
The infectivity of the viruses was tested by CC- RT-PCR for rotaviruses and by CC-PCR for adenoviruses. In further investigation , we choose some of the positive Samples to be subjected to sequence analysis to determine the most common serotypes and strains.
The results of this study could be summarized as following:
The frequency of rotaviruses in water samples which collected from El-Giza water treatment plant in different treatment steps from July 2009 to June 2011 are 29.16% ( 7/ 24), 25% (6/24) , 20.8% (5/24) and 12.5% (3/24) in raw water , after sedimentation , after sand filtration and after chlorination; respectively. While the Frequency of Adenoviruses in the same water samples are 70.8 % (17/24), 62.5 %( 15/24) 37.5 %( 9/24) and 25 % (6/24) in raw water, after sedimentation, after sand filtration and after chlorination; respectively.
The Frequency of rotaviruses in sewage samples which collected from Zenin wastewater treatment plant in different treatment steps from July 2009 to June 2011 are 16.7%(4/ 24),20.8% (5/24) ,16.7% (4/24) and 16.7% (4/24) in raw sewage , after primary treatment , after secondary treatment and after chlorination ; respectively, while The Frequency of Adenoviruses in the same samples were 91.6%(24 /22) in raw sewage, 87.5 %24/20) ) after primary treatment, 75% /18/)24) after secondary treatment and 50%(11/24) after chlorination ; respectively.
The number of human rotaviruses genome in positive RT- PCR samples of El-Giza WTP ranged from 9x10 to 5x105 RNA copies/1 While, the number of human rotaviruses infectious units ranged from 2x10 to 1x104 CC-PCR unit/1 in Nile water samples. 1 log reduction was observed after sedimentation. 0 to 1 log reduction was observed after sand filtration and 1 to 3 log reduction was observed after final chlorine for rotavirus genome. 0 to 1 log reduction was observed after sedimentation. 0 to 1 log reduction was observed after sand filtration. 1 to 3 log reduction was observed after final chlorine for rotavirus infectious units. 0 to 2 log difference was observed between rotaviruses genome and infectious units.
The number of human rotavirus genome in positive RT-PCR samples of Zenin WWTP ranged from 7x103 to 2x107 RNA copies/1 while, the number of human rotavirus infectious units ranged from 1x102 to 5x105 CC-PCR unit/1 in raw sewage samples. 1 log reduction was observed after primary sedimentation. 1 to 2 log reduction was observed after secondary sedimentation. 2 to 3 log reduction was observed after final chlorine for rotavirus genome. 0 to 1 log reduction was observed after primary sedimentation. 1 to 2 log reductions was observed after secondary sedimentation and 1 to 3 log reduction was observed after final chlorine for rotavirus infectious units. 0 to 3 log difference was observed between rotaviruses genome and infectious units.
The number of human adenovirus genome in positive PCR samples of El-Giza WTP ranged from 9x10 to 8x105 DNA copies/1 While, the number of human adenoviruses infectious units ranged from 8x10 to 9x104 CC-PCR unit/1 in Nile water samples. 0 to 1 log reduction was observed after sedimentation. 0 to 1 log reduction was observed after Sand filtration. 0 to 2 log reduction was observed after final chlorine adenoviruses genome. 0 to1 log reduction was observed after sedimentation. 1 to 2 log reduction was observed after sand filtration to 2 log reduction was observed after final chlorine adenoviruses infectious units. 0 to 3 log difference was observed between adenovirus genome and infectious units.
The number of human adenovirus genome in positive PCR samples of Zenin WWTP ranged from 9x10 to 6x107 DNA copies/1 while, the number of human adenoviruses infectious units ranged from 1x10 to 4x105 CC-PCR unit/1 in raw sewage samples. 0 to 1 log reduction was observed after primary sedimentation. 0 to 2 log reductions was observed after secondary sedimentation and 1 to 2 log reduction was observed after final chlorine for adenoviruses genome. 0 to 1 log reduction was observed after primary sedimentation. 0 to 2 log reduction was observed after secondary sedimentation and1 to 2 log reduction was observed after final chlorine for adenoviruses infectious units. 0 to 3 log difference was observed between adenovirus genome and infectious units.
A total of 110 stool specimens were obtained from children under 5 years of age who presented with acute diarrhea during May 2011 to April 2012 from Abo-El Rish hospital in Great Cairo, 24 out of 110 samples were positive for Adenoviruses, while 35 out of 110 samples were positive for rotaviruses. The rotaviruses exhibit an obvious seasonal variation were the highest frequency of rotaviruses were detected during the winter season (the peak of rotaviruses) in (November, December, January, February). While the lowest frequency was detected during the spring and the summer seasons (all samples were negative in (July and August). On the other hand, no peak for adenoviruses was noticed in this study (the Frequency of adenoviruses was Homogeneous all over the year). The coinfection was noticed in several months during this study, especially during the cold season, the numbers of coinfected samples were 11 out of 110.
Sequence analysis of 24 PCR positive adenovirus samples were carried out, the result indicated that 19 samples (6 raw sewage, 5 Nile Water and 8 clinical samples) showed similar sequence cluster with human adenovirus 41 strain 503804/KOL / 2009 hexon gene with 94% homology. It indicated also that 5 PCR positive adenovirus samples (2 raw sewage and 3 Nile water samples) showed similar sequence cluster with human adenovirus 2 strain N3773 /TW/ 05-2 hexon gene with 98% homology. Sequence analysis of 16 RT-PCR positive rotavirus samples (4 row sewage, 4 Nile water and 8 clinical samples) showed that all the sequences clustered with rotavirus VP6 with 98% homology.
The result of the present study showed that adenoviruses were more frequent in water samples and sewage samples than rotaviruses. However, rotaviruses (Known as the most common virus associated with gastroenteritis) were more frequent in stool samples than adenoviruses.
At the same time both viruses showed great resistant to treatment process in water treatment plant and in waste water treatment Plant. Therefore we concluded that adenoviruses (not only enteric adenoviruses) could serve as a possible indicator of viral pollution in the Egyptian aquatic environment due to its high frequency, stability and resistance to chemical. However, more studies on different types and sources of water in the Egyptian aquatic environment are needed to choose the best virus to serve as indicator of viral pollution in water.