The results of the laboratory tests of the National Network of Sewage Epidemiology for the epidemiological surveillance of the SARS-CoV-2 virus in urban wastewater, which operates under the coordination of EODY, were announced by EODY.
The samples come from the Attica Region and the cities of Thessaloniki, Larissa, Volos, Heraklion, Chania, Rethymnon, Agios Nikolaos Lassithi, Patras, Xanthi, Alexandroupolis, Ioannina and Corfu. Samples are taken from the entrances of the local Wastewater Treatment Plants
(MEL) and correspond to the population served by them.
Table 1: Percentage change in the mean SARS-CoV-2 viral load concentration in urban wastewater per 100,000 inhabitants in the week of October 25-31, 2021 compared to the week of October 18-24, 2021
Conclusions: During the week 25 to 31 October 2021, there were increasing trends compared to the week 18 to 24 October 2021, in the average weekly viral load of SARS-CoV-2 in the urban wastewater of six of the twelve areas controlled by the National Network of Sewage Epidemiology (EDEL) of EODY. Net increases were observed in Heraklion (+ 39%), Thessaloniki (+ 45%), Volos (+ 78%) and Ioannina (+ 223%), while marginal increases were observed in the urban wastewater of the Attica Region (+ 19%) and Agios Nikolaos (+ 15%).
Marginal reductions in the average weekly viral load of urban wastewater were observed in Larissa (-10%), Chania (-13%), Xanthi (-21%), Alexandroupoli (-23%) and Patras (-28%) , with the changes falling within the limits of laboratory uncertainty. The viral load in the urban wastewater of the city of Corfu was below the quantification threshold of the method and, therefore, undetectable.
Region of Attica: In the last week, 25-31 / 10/21, the average weekly viral load in the urban wastewater of the Attica Region showed a marginal increase, with a statistically insignificant change (+ 19%) of the weekly average compared to the previous week, 18- 24/10/21.
Thessaloniki: In the last week, 25-31 / 10/21, in Thessaloniki, the weekly average value of the viral load of urban wastewater showed an increase (+ 45%) compared to the previous week, 18-24 / 10/21. The upward trend in the viral load of sewage in the city of Thessaloniki started in mid-September 2021 (week 13-19 September). Since then, the viral load has been constantly increasing, while the last three weeks have seen a higher growth rate. Overall, the weekly average value of the viral load from mid-September to date has
quadrupled.
Larissa: In the last week, 25-31 / 10/21, the average weekly viral load of urban wastewater in Larissa showed a marginal decrease (-10%) compared to the week 18-24 / 10/21. Viral load levels remain particularly high. The upward trend in the viral load of the wastewater of the city of Larissa started in mid-September
8 2021 (week 13-19 September). Overall, the weekly average value of the viral load from mid-September to date has increased eightfold.
Marble: In the last week, 25-31 / 10/21, the average weekly viral load of urban wastewater in Volos increased (+ 78%) compared to the week 18-24 / 10/21. Viral load levels remain particularly high. The upward trend in the viral load of sewage in the city of Volos started in mid-September 2021 (week 13-19 September). Overall, the weekly average value of the viral load from mid-September to date has increased elevenfold.
Heraklion: In the last week, 25-31 / 10/21, the viral load in Heraklion showed an increase (+ 39%) compared to the previous week, 18-24 / 10/21.
Chania: Last week, 25-31 / 10/21, the viral load in Chania showed a marginal decrease (-13%) compared to the previous week, 18-24 / 10/21.
Saint Nicholas: In the last week, 25-31 / 10/21, the average weekly viral load in Agios Nikolaos showed a marginal increase (+ 15%) compared to the previous week 18-24 / 10/21.
Patras: In the last week, 25-31 / 10/21, in Patras, a constant presence of viral load was observed in the urban wastewater of the city with a marginal decrease (-28%) of this weekly average, compared to the previous week, 18-24 / 10/21.
Blonde: In the last week, 25-31 / 10/21, the average weekly viral load of urban wastewater in Xanthi showed a marginal decrease (-21%) compared to the week, 18-24 / 10/21. Viral load levels remain particularly high. The upward trend in the viral load of sewage in the city of Xanthi started in mid-September 2021 (week 13-19 September). Overall, the average weekly viral load has tripled since mid-September.
Alexandroupoli: In the last week, 25-31 / 10/21, in Alexandroupolis, there was a marginal decrease (-23%) in the average weekly viral load of urban wastewater compared to the week 18-24 / 10/21. Viral load levels remain particularly high. The upward trend in the viral load of the wastewater of the city of Alexandroupolis started from mid-September 2021 (week 13-19 September). Overall, the weekly average value of the viral load from mid-September to date has increased by 3.5 to 4 times.
Janina: In the last week, 25-31 / 10/21, in Ioannina, the average weekly viral load of urban wastewater showed a significant increase (+ 223%) compared to the previous week, 18-24 / 10/21.
Corfu: In the last week, 25-31 / 10/21, in the city of Corfu, no viral load was detected in the urban wastewater of the city, ie its levels were below the limit of quantification of the method of its detection and measurement.
Note: The laboratories participating in the network are: Laboratory of Analytical Chemistry of the National and Kapodistrian University of Athens, Interdisciplinary Laboratory Team of Sewage Epidemiology of the Aristotle University of Thessaloniki, Peripheral Laboratory of Public Health of the Republic , Laboratory of Hygiene and Epidemiology of the Department of Medicine of the University of Ioannina.
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