Monitoring the evolution of Covid-19 in wastewater
Researchers at the Luxembourg Institute of Science and Technology (LIST) are working tirelessly to provide a detailed view of the evolution of the Covid-19 pandemic by tracking the presence of the coronavirus in Luxembourg’s wastewater. Using a highly sensitive methodology, LIST’s team of microbiologists identifies where, when and in what concentration the SARS-CoV-2 coronavirus is present. Complementary to the large-scale testing, these near real-time results are delivered weekly to the government for an informed decision.
What are the wastewater analyses?
In collaboration with the Administration de la gestion de l’Eau (Water Management Administration) and Aluseau (Luxembourg Water and Wastewater operators association), LIST researchers collect samples of wastewater from each strategic wastewater treatment plant in Luxembourg. They then concentrate and analyse these samples in the laboratory, in particular by carrying out a Polymerase Chain Reaction, better known as PCR. This process, identical to that used for large-scale tests, is highly sensitive and reliable. It enables the virus to be detected in minute concentrations by recognising fragments of its genetic identity card.
Frequently Asked Questions
When are the latest results of the study published?
The weekly or even bi-weekly results of the analyses of the presence of coronavirus in wastewater are first communicated to the Government and published on this page within 24 to 48 hours. The conclusions of these analyses are also included in a global report of the actors in the fight against the pandemic and published every Wednesday on the Ministry of Health website.
How to understand these graphs?
Graphs show the evolution of the number of positive cases in parallel with the number of copies of the genetic material of the SARS-CoV-2 coronavirus found in Luxembourg over time. It is therefore possible to see that the trends of the two curves are relatively similar. However, no correlation can be made to date: the curve of coronavirus in wastewater does not indicate the estimated number of positive cases. LIST researchers are currently working with mathematicians and modellers to establish how many people are infected based on the results found in wastewater.
Can these analyses predict the evolution of the pandemic in Luxembourg?
The high sensitivity and reliability of the methodology developed by LIST researchers makes it possible to follow the evolution of the presence of the coronavirus in wastewater in almost real time. In comparison and complementarity of clinical tests, this wastewater monitoring provides earlier information – approximately 24 to 48 hours – on the evolution of the virus circulation throughout the country but is not intended to provide predictions. However, this methodology has made it possible to go back in time and find the first traces of SARS-CoV-2 on Luxembourg soil as early as February, thanks to samples of wastewater dating from that time.
How did the idea of monitoring the evolution of the pandemic through wastewater come from?
This respiratory tropism virus is different from other viruses known until now. LIST researchers therefore did not expect that it would be possible to detect it in the faeces. As soon as they became aware of it at the beginning of 2020, the CORONASTEP team mobilised to be able to detect and monitor it in Luxembourg’s wastewater.
LIST has a strong experience in monitoring the spread of viruses within wastewater. Researchers already have adequate methodologies and protocols for monitoring gastroenteritis viruses, for example.
From the collection of samples to the analysis and interpretation of results in the laboratory, the Coronastep project team led by Leslie Ogorzaly and Henry-Michel Cauchie is using its expertise in environmental microbiology and hydrology to fight the Covid-19 pandemic:
- Dr Henry-Michel Cauchie
- Dr Leslie Ogorzaly
- Cécile Walczak
- Delphine Collard
- Dr Christian Penny
Research Luxembourg is a joint initiative of the main players in Luxembourg public research Luxembourg Institute of Health (LIH); Luxembourg Institute of Socio-Economic Research (LISER); Luxembourg Institute of Science and Technology (LIST); Laboratoire National de santé (LNS); University of Luxembourg; Fonds National de la Recherche (FNR), supported by the Ministry of Higher Education and Research. The main aim of the initiative is to promote scientific cooperation in Luxembourg and to communicate the activities of the sector as a whole.
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