How hard to survive your life in something unknown, from something that you cannot see with your naked eyes!
It’s just like getting into a maze full of snakes while you are blindfolded; all you have to do is survive!
Moreover, you are forced not to be afraid, because fear will weaken your defense systems.
It’s the same case with Covid 19, an invisible dangerous virus with new symptoms.
What is the nature of this virus? How can it be transmitted?
Has this virus the ability to survive in water? What if it has?
What is (COVID-19)?
The virus COVID-19 is brought on by a brand-new coronavirus known as SARS-CoV-2.
Following a report of a cluster of “viral pneumonia” cases in Wuhan, the People’s Republic of China, WHO first learned of this new virus on December 31, 2019.
The most typical COVID-19 signs and symptoms include fever, Dry cough and weakness
less frequent symptoms that some people may experience include as follows:
1-Loss of scent or flavor.
2-Conjunctivitis (also known as red eyes.
3-Throat pain.
4-Joint or muscle discomfort.
5-Diverse skin rash types.
6-Vomit or nausea.
7-Dizziness or chills.
Severe COVID-19 illness symptoms include:
1-Difficulty breathing.
2-decrease in appetite.
3-Persistent chest pressure or pain.
4-Extreme heat (above 38 °C).
The transmission mechanism of covid 19 to wastewater
Since there is no direct contact with an infected person, all secondary mechanisms can be considered.
Contact (COVID-19) wastewater aerosols may be one of these secondary mechanisms.
The virus has been found in feces and hospital and domestic wastewater both contain high viral concentrations of 104 genomic copies.
Workers in wastewater treatment plants may come into touch with these wastewater aerosols.
Patients in hospitals or those who are quarantined at home can spread the infection via wastewater.
The risk of transmission is higher in nations where wastewater is not treated.
COVID-19 detection in wastewater
As wastewater analysis has proven to be an important technique for tracking and controlling emerging coronavirus outbreaks.
According to the Government Accountability Office, wastewater surveillance may have immense promise as a public health tool, but some areas of the research may require further refinement.
For years, wastewater treatment facilities have used analytical procedures that have been notably successful in combating the development of COVID-19.
The Centers for Disease Control and Prevention has updated its COVID-19 dashboard with wastewater testing results.
Using wastewater analysis, researchers discovered unknown coronavirus strains.
As national testing for COVID-19 diminishes, experts see wastewater as an increasingly important tool for tracking its spread.
Based on the concentrations of SARS-CoV-2 in wastewater, various testing techniques and laboratory workflows enable approaches to be adjusted to higher or lower detection limits as required.
Testing approach: RNA method
Preparation of the sample
It’s the fundamental step and if carried out correctly, will undoubtedly produce accurate results.
1-Storage: To prevent RNA degradation and improve the usefulness of surveillance, store the samples at 4°C in the refrigerator as soon as they are collected.
If at all possible, process the samples within 24 hours.
2-Homogenization: Before removing parts of the collected wastewater for downstream processing, it is important to thoroughly mix both liquid wastewater and primary sludge samples.
Procedures that break up wastewater sediments and disaggregate virus particles, such as via sonication, can also be included inhomogeneous samples.
3-Sample clarification: liquid wastewater samples are utilized for sample concentration, clarifying the samples by removing big particulates can help subsequent filtration-based concentration processes.
Sample concentration
Concentrating wastewater samples can enhance SARS-CoV-2 RNA detection.
Concentration may be more crucial for primary sludge samples as opposed to untreated wastewater samples.
The concentration methods that have been tested so far and provide sufficient recovery for SARS-CoV-2 detection in wastewater include:
1-Filtration using an electronegative membrane combined with sample preparation using either acidification or the addition of MgCl2.
2-Precipitation of polyethylene glycol (PEG).
3-milk flocculation in skim.
Extraction of RNA
It is crucial to separate and purify nucleic acids before isolating SARS-CoV-2 RNA from the sewage mixture.
So, bear the following in mind while choosing an extraction technique:
Pick an extraction technique that will result in extremely pure nucleic acid extracts from environmental materials.
For the extraction of environmental samples, commercial kits are available.
Utilize a purification procedure or RNA-specific extraction kit that contains RNase denaturants before lysis.
By aliquoting extracts into different tubes and keeping them at -70°C or below, you can prevent the destruction of isolated RNA due to repeated freeze-thaw cycles.
Laboratory controls
When using various testing techniques and comparing SARS-CoV-2 RNA wastewater quantities over time and across diverse wastewater sources, laboratory controls are crucial.
Types of laboratory controls for measurements
Control for matrix recovery: Learn how much virus was lost during sample processing by using a matrix recovery control, also known as process control.
fecal normalization in humans: To evaluate SARS-CoV-2 concentrations and compare concentrations between sewage samples over time, adjusting SARS-CoV-2 concentrations by the proportion of human excrement in wastewater can be crucial.
Controls for quantitative measurements: To prevent freeze-thaw cycles, aliquot quantitative measurement controls and store them at -70°C or lower.
Inhibition assessment: To check whether RNA quantification procedures (RT and PCR) are working as predicted, use inhibition testing.
Negative checks: Include these controls with all PCR instrument runs to identify molecular reagent contamination.
New low-cost detection method
Researchers from the Indian Institute of Technology (IIT) Bombay and the University of Strathclyde have devised a low-cost sensor that can find COVID-19 viral pieces in wastewater.
The biosensor detects SARS-CoV-2 nucleic acid fragments that have bonded with the widely accessible salt methylene blue, which is added to the sample to give a quantifiable electrochemical signal, using printed circuit board electrodes.
They discovered that even at concentrations as low as 10 picograms per microliter (pg/l), the sensor could detect the genetic material.
The electrodes have a long shelf life, are reusable, are simple to clean and do not experience any alterations that would impair their performance.
Dr. Siddharth Tallur, an adjunct professor in the Electrical Engineering Department of IIT Bombay, said:
The method we have developed is not just applicable to SARS-CoV-2, it could be applied to any other virus so it’s very versatile.
Why do we need to detect Covid_19 In wastewater?
SARS-CoV-2 levels in wastewater from large populations are an effective predictor of a community’s infection level.
Wastewater monitoring does not rely on the availability of clinical tests or individuals reporting their test findings.
It also detects asymptomatic and pre-symptomatic COVID-19 infections, which is important because people who are infected but do not feel sick can still transfer COVID-19.
Observing virus levels in sewage fluctuate provides insight into whether cases are increasing or decreasing in the community as a whole.
Data from sequencing can also be used to find new variants and monitor their levels, allowing health responses to take into account the variant’s features.
(COVID-19) impact on water supplies
Because COVID-19 is a new virus, research is still being undertaken to better understand its features, such as viability, survival time, migration patterns and transmission paths, and inactivation by standard disinfection techniques.
Disinfection is a technique used in water treatment technologies to get rid of bacteria and viruses from the finished drinking water.
Except for ozone, which has a very high disinfecting efficiency in viruses, drinking water disinfection is more successful against bacteria than viruses.
Additionally, according to the World Health Organization, viruses are more resistant to free chlorine than bacteria are.
The SARS CoV-2 virus, however, is only very little resistant to chlorine treatment, according to recent studies.
Thus, it is possible to prevent chlorine from contaminating water with SARS-CoV-2.
This is because coronavirus is an enclosed virus and the loss of the receptor is caused by the deterioration of the virus’s envelope.
In this manner, the virus no longer spreads.
It was important to determine whether the illness could also spread through wastewater.
According to many studies, up to 10% of Covid-19 patients had diarrhea, which raises the possibility of viral transmission through sewage.
Impact of COVID-19 epidemic on drinking water purification facility
The damage caused to the water purification facility due to the outbreak of the corona epidemic increased the rate of water consumption more than normal, which increased the pressure on the workers of the water purification plant.
References
4-https://www.cdc.gov/healthywater/surveillance/wastewater-surveillance/testing-methods.html
5-https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8397333/
7- https://www.watercom/doc/how-wastewater-monitoring-could-help-head-off-future-outbreaks-0001
