Background
Methods
Sewage sample collection
Clinical sample collection
Sewage sample processing
Stool sample processing
Cell culture
Inoculation of sewage samples
Inoculation of stool samples
Identification of enteroviruses
Micro-neutralization assay
Virus isolation
RT-PCR for enterovirus
RT-PCR product purification
PCR product sequencing
Alignment and phylogenetic analysis
Results
Year | No. of EVs isolated from sewage | Total | No. of EVs isolated from patients | Total | ||||||
---|---|---|---|---|---|---|---|---|---|---|
PV | CBV | Echo virus | UT | PV | CBV | Echo virus | UT | |||
2007 | 01 | 02 | 06 | 02 | 11 | 04 | 03 | 11 | 04 | 22 |
2008 | 04 | 01 | 11 | 05 | 21 | 09 | 08 | 18 | 11 | 46 |
2009 | 02 | 02 | 04 | 04 | 12 | 08 | 05 | 04 | 13 | 30 |
Total | 07 | 05 | 21 | 11 | 44 | 21 | 16 | 33 | 28 | 98 |
Clinical isolates analysis
Year | No. of NPEV isolated from sewage | Total | No. of NPEV isolated from Patient | Total | ||
---|---|---|---|---|---|---|
No. of typed NPEV | No. of untyped NPEV | No. of typed NPEV | No. of untyped NPEV | |||
2007 | 08 | 02 | 10 | 14 | 04 | 18 |
2008 | 12 | 05 | 17 | 26 | 11 | 37 |
2009 | 06 | 04 | 10 | 09 | 13 | 22 |
Total | 26 | 11 | 37 | 49 | 28 | 77 |
Sewage isolates analysis
Comparison between clinical and sewage EVs
Percentage of Clinical virus Isolates / Percentage of sewage Isolates | |||||||||
---|---|---|---|---|---|---|---|---|---|
Virus | 2007 | 2008 | 2009 | ||||||
July- Sep. | Oct- Dec. | Jan.- March | April–June | July- Sep. | Oct. – Dec. | Jan.- March | April–June | July- Sep. | |
N/N | 12/6 | 10/5 | 9/4 | 11/5 | 14/8 | 12/4 | 11/4 | 8/4 | 11/4 |
E3 | 0/0 | 0/0 | 0/25.0 | 0/0 | 0/0 | 0/0 | 0/0 | 0/0 | 0/0 |
E4 | 16.6/0 | 0/0 | 0/0 | 9.0/0 | 0/0 | 0/0 | 0/25.0 | 0/0 | 0/0 |
E6 | 16.6/16.6 | 0/0 | 0/0 | 0/0 | 0/0 | 0/0 | 0/0 | 0/25.0 | 0/0 |
E7 | 0/0 | 10.0/0 | 0/25.0 | 0/0 | 7.1/12.5 | 0/0 | 9.0/0 | 0/0 | 0/0 |
E9 | 8.3/33.3 | 10.0/0 | 11.1/0 | 9.0/20.0 | 0/0 | 8.3/0 | 0/25.0 | 0/0 | 0/0 |
E11 | 8.3/0 | 20.0/20.0 | 0/0 | 0/0 | 14.3/12.5 | 8.3/0 | 0/25.0 | 0/0 | 0/0 |
E12 | 8.3/0 | 0/0 | 11.1/0 | 0/0 | 0/0 | 16.3/0 | 0/0 | 0/0 | 0/0 |
E13 | 0/0 | 0/0 | 0/0 | 0/20. | 0/0 | 0/25.0 | 0/0 | 0/0 | 0/0 |
E25 | 0/0 | 0/20.0 | 11.1/0 | 0/0 | 0/12.5 | 8.3/0 | 0/0 | 0/0 | 9.0/0 |
E29 | 0/0 | 0/0 | 0/0 | 9.0/0 | 0/0 | 0/0 | 9.0/0 | 0/0 | 0/0 |
E30 | 0/0 | 0/20.0 | 11.1/0 | 9.0/20.0 | 7.1/0 | 0/25.0 | 0/0 | 0/0 | 0/0 |
E33 | 0/0 | 0/0 | 0/0 | 0/0 | 0/12.5 | 8.3/0 | 0/0 | 12.5/0 | 0/0 |
CB | 0/16.6 | 30.0/20.0 | 22.2/0 | 9.0/0 | 14.3/12.5 | 25.0/0 | 9.0/25.0 | 25.0/0 | 18.2/25.0 |
PV | 16.6/0 | 20.0/20.0 | 22.2/0 | 18.18/20.0 | 21.4/25.0 | 16.6/25.0 | 27.3/0 | 12.5/0 | 36.4/25.0 |
UT | 25.5/33.3 | 10/0 | 11.1/40.0 | 36.3/20 | 35.7/12.5 | 8.3/25.0 | 45.5/0 | 50.0/75.0 | 36.4/50.0 |
Yearly analysis (2007)
Year 2008
Year 2009
Discussion
Conclusion
Highlights
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Coxsackieviruses, untypable isolates, and serotypes of E9 and E11 were most frequently detected viruses throughout in clinical and sewage samples.
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There was a close relation among the stereotypes of enteroviruses shed in stools and isolated from the environment, but few serotypes which were detected in sewage samples were not found clinically and the few which were detected clinically not found in sewage because some viruses are difficult to detect by the cell culture method.
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To improve the correlation between sewage and clinical cases we can use the real time PCR method and also there is a need to increase surveillance system.