Increasing trends were observed in the SARS-CoV-2 viral load in the urban wastewater of nine of the twelve areas tested by the National Wastewater Epidemiology Network of the National Wastewater Authority, during the week of 12 to 18 July.
The net incremental changes ranged from +34% in Larissa to +260% in Thessaloniki. The increase in Rethymno (+24%) is considered marginal.
Decreasing changes were observed in two of the twelve regions of the National Wastewater Network, namely Volos (-68%) and Heraklion (-74%).
In Xanthi the viral load remained very low but was detectable, i.e. levels were above the quantification limit of the method, in contrast to the previous week, 5-11/7/21, when levels were below the quantification limit of the method and undetectable.
Region of Attica: During the last week, 12-18/7/21, the viral load in urban wastewater in the Region of Attica showed a statistically significant increase (+219%) of the weekly average compared to the previous week, 5-11/7/21, with the viral load in wastewater now at high levels.
Thessaloniki: During the last week, 12-18/7/21, in Thessaloniki, a significant increase (+260%) in the viral load of urban wastewater was observed compared to the week 5-11/7/21. The increasing trend of the viral load was strong at the beginning of the last week, while it normalized afterwards.
Larissa: A further increase (+34%) in the viral load of urban wastewater in Larissa was observed.
Volos: A decrease (-68%) in viral load levels was observed in Volos.
Heraklion: A decrease (-74%) of the weekly average in the viral load of urban wastewater was recorded. The concentration of viral load in urban wastewater in the city continues to be characterized as moderate to relatively high.
Chania: An increase (+176%) in the weekly average of the viral load in urban wastewater was recorded. The concentration of viral load in urban wastewater in the city is characterised as moderate.
Rethymno: A further increase (+24%) in the weekly average viral load in municipal wastewater was recorded compared to the week 5-11/7/21. Despite the marginal increase, the viral load values are characterized as relatively high.
St. Nicholas: An increase (+110%) was observed compared to week 5-11/7/21. Despite the increase recorded, the viral load remains at relatively low to moderate levels.
Patras: A steady increase (+35%) was observed in the viral load of urban wastewater.
Xanthi: Genetic material of the virus was detected in the urban wastewater of Xanthi, but at very low levels.
Alexandroupolis: An increase (+255%) was observed in the viral load of urban wastewater in Alexandroupolis compared to the week 5-11/7/21. It is noted that the above percentage change is calculated compared to the previous week (5-11/7/21) during which the viral load levels were extremely low.
Ioannina: The average weekly viral load in wastewater showed an increase (+48%) compared to the week 5-11/7/21.
