There is a persistent yet very slow decline in coronavirus levels in wastewater, the University of Tartu's latest monitoring study has confirmed. There is still a large amount of virus present across Estonia and achieving a moderate level could still take several weeks.
The current spread of the virus is comparable to that of the beginning of February when cases started to quickly increase.
Lead researcher, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, said the decline in the amount of virus in wastewater started in the second half of March and is now noticeable in all regions.
"However, the decrease rate is very modest and the amount of virus in wastewater continues to be uniformly high across Estonia. Thus, it is still weeks before we can expect a significant change and reach the moderate level," Tenson said.
The results from the most recent study (April 12-16) can be seen below. The situation has improved in south Estonia and several samples in Võru, Pärnu and Viljandi counties are now marked in green.
The study from the previous week is shown below, and there were only two green samples, both in Põltsamaa, central Estonia.
How and where are the samples collected?
Wastewater samples are collected at the beginning of every week in all county centers, cities with more than 10,000 inhabitants and, if necessary, in smaller settlements.
Samples taken from larger cities reflect the situation of wastewater passing through the treatment plant over 24 hours, giving a reliable overview of the infection level in the city.
In smaller places, spot samples are taken, showing the virus level in wastewater at the moment of sampling. Spot samples are more easily affected by various factors and should therefore be used over several weeks to estimate the trend, rather than get a definitive picture of the current situation.
For more information and the interactive map with the previous results of the study, see the home page of the study "Detecting coronavirus in waste water".
Editor: Helen Wright