Costa Rica has the first results of studies to monitor the coronavirus that causes Covid-19 in wastewater. The analyzes of the Costa Rican Institute of Aqueducts and Sewers (AyA), in coordination with the Ministry of Health and the Costa Rican Social Security Fund (CCSS), confirm the presence of SARS-CoV-2 in the wastewater of the Central Regional Apprehension Center (CARC) with a sample from May 7, when 12 people confirmed with the disease were there.
“It is an achievement for Costa Rica to have a program to detect SARS-CoV-2 in wastewater, as it will strengthen virus monitoring in different communities in the country,” said Health Minister Daniel Salas.
During this week, the AyA National Water Laboratory (LNA) collects and analyzes new samples from the Mexico Hospital, Alajuela Hospital, Specialized Patient Care Center with Covid-19 (CEACO) and the Los Tajos wastewater treatment plant .
“The analyzes we are carrying out meet the highest demands of the best laboratories in the world. These function as a photograph that tells us if there is a SARS-CoV-2 in a certain area, ”said AyA Executive President Yamileth Astorga.
During the first stage of validation of the test, with samples from mid-April, the AyA did not detect SARS-CoV-2 in the wastewater treatment plants of Los Tajos (San José), which serves some 200,000 people, and another from La Guácima, which serves 1000. In these two cases, the non-detection of the virus on that date could be due to the low circulation of SARS-CoV-2 in the population covered by the sewerage service, which is consistent with monitoring carried out by public health authorities through other channels.
The international scientific community has shown that a varied percentage of patients with Covid-19 disease excrete particles of the new coronavirus in the faeces.
Quantify the virus
At the moment, AyA studies confirm the presence or not of SARS-CoV-2, but later the concentration of the virus present in different samples can be measured and comparisons can be made to estimate the virus burden in the population that serves the sewerage. .
For these purposes, the institution manages the purchase of new supplies that would be arriving in the country in June. In addition, long-term studies would show the seasonality patterns that the virus may present.
The application of these tests places Costa Rica as one of the pioneer countries in Latin America, following the example of countries such as Brazil, the United States, the Netherlands, Japan, France and Australia.
Analyzing the presence of the new coronavirus in wastewater has a high degree of complexity, which involves reducing the inhibitory effect of some substances such as detergents, medications and other chemicals, which can affect the analyzes. It is important to clarify that there is no scientific evidence that the virus is transmitted in wastewater.
The LNA has experience in detecting viruses and pathogens in wastewater, surface water and seawater. Other studies in Jacó and Puntarenas have allowed the identification of noroviruses, adenoviruses, as well as other microbial indicators, thanks to an agreement with the University of South Florida (USF).
The LNA was recognized in March 2019 as the “Regional Reference Laboratory for Wastewater 2018-2023” by the United States Environmental Protection Agency (EPA).