Waste water study confirms high prevalence of coronavirus also in north eastern Estonia

This week’s results of the waste water study led by the University of Tartu predict that the number of coronavirus infections will increase in the coming weeks not only in Harju County and southern Estonia, but also in Ida-Viru County. Waste water samples from western Estonia show somewhat lower virus concentrations.

According to the lead researcher of the study, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, the percentage of samples with very high virus content has grown steadily for a month already. “Virus amounts have increased significantly above the Estonian average in Harju Country, southern Estonia, as well as in Ida-Viru County. Among settlements, the largest increase in viruses has been recorded in Viljandi, Sillamäe, and the Jõhvi-Ahtme region,” said Tenson. Of the larger settlements in southern Estonia, the map does not contain the data for Valga, because researchers were unable to determine the coronavirus amounts there due to the high concentration of additives in the water sampled from the treatment plant.

How and where are the samples collected?

Waste water samples are collected at the beginning of every week in all Estonian county centres, cities with more than 10,000 inhabitants and, if necessary, in smaller settlements. Samples taken from larger cities reflect the situation of waste water 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 waste water 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.

The study is a tool helping the Health Board monitor changes in the outbreak dynamics and discover hidden outbreaks. It gives early information to estimate the spread of the virus before clinical cases are detected. The Health Board is regularly informed of the results.

In collecting the samples, the University of Tartu cooperates with the Estonian Environmental Research Centre and water companies operating the waste water treatment plants of Estonian cities. The samples are analysed at the laboratories of the University of Tartu Institute of Technology.

For more information about the previous results of the study, see the home page of the study “Detecting coronavirus in waste water”.

Further information: Tanel Tenson, Professor of Technology of Antimicrobial Compounds, University of Tartu, 5344 5202, tanel.tenson@ut.ee