Will the history of the COVID-19 pandemic have to be rewritten after the discovery of Spanish scientists?

The earliest cases of coronavirus infection were previously thought to have appeared in 2019. November in Uhane, even before 2019. in late 2020 In the early 19th century, the public became aware of the new infectious disease.

But now a team of scientists, led by the respected Spanish virologist Albert Bosch of the University of Barcelona, ​​claims that traces of Sars-CoV-2 were detected in Barcelona’s wastewater in March last year.

Still, some scientists, such as geneticist Fernando González, have criticized the study. “There are cities with more foreign tourists than Barcelona, ​​but they did not detect the virus in retrospective wastewater tests.” I would be inclined to postpone the results of this study and carry out an independent study, ”the researcher told El País.

A new discovery

The new SARS-CoV-2 coronavirus may live longer in Europe than previously thought. Recent research has shown that he was already in Italy as early as 2019. in December. But researchers at the University of Barcelona have made an even more surprising discovery: They found traces of the virus by examining untreated sewage samples dating back to 2019. March 12, The Conversation writes.

The study was recently published on the MedRxiv website for unpublished articles on health sciences. The article is being prepared for publication in a scientific journal and is being reviewed by external experts. Until this review and evaluation process is complete, the article findings should be treated with caution.

So how was the experiment conducted and what exactly did the scientists discover?

One of the first findings about SARS-CoV-2 is that the virus is found in the feces of infected people. As the virus travels through the intestine, where it can cause gastrointestinal symptoms, it loses its outer protein layer, but a particle of genetic material called ribonucleic acid (RNA) survives the journey and remains intact. It is excreted in the faeces. At the time, it’s no longer contagious, at least that’s what the evidence now shows.

However, the fact that these coronavirus RNA particles can be found in untreated wastewater is useful for monitoring and tracking outbreaks. According to them, it is indeed possible to predict where the outbreak is likely to occur, one week to ten days before official data is available.

This is because people secrete coronaviruses before symptoms are noticed. These people, who have not yet developed symptoms, should get sick enough to get tested, receive the results, and probably go to the hospital, about a week after the stool is excreted in the stool.

As a result, many countries, including Spain, are investigating wastewater and looking for traces of coronaviruses. In the case of the aforementioned wastewater study, epidemiologists examined frozen wastewater samples. The wastewater collected since 2018 was analyzed. January to 2019 December: to find out when the virus first appeared in the city.

The researchers discovered that there were traces of the virus in 2020. January 15 – 41 days before 2020. February 25, the date the first case of coronavirus was officially recorded. All other samples tested to date were negative except in 2019. On March 12 sample, the coronavirus test was positive. A standard test was performed to determine if you had coronavirus at the time.

For this test, samples of saliva, mucus, frozen effluents, or other items suspected of lying in wait for the virus can be used. All unnecessary material is removed from the sample, and then RNA, a single strand of genetic material, is converted to DNA, a double helix.

DNA is then “amplified” in successive cycles until the most important particles in the genetic material, known to exist only in a particular virus, are sufficient to be captured by a fluorescent probe.

Lack of precision

When studying the coronavirus, researchers often look for more than one gene. In this case, the study authors analyzed three genes. Positive in 2019 The result of the March sample was detected in one of the three genes tested, the RdRp gene. The researchers looked at two regions of this gene. Both were detected only during the amplification of 39 cycles. As the number of amplification cycles increases, the accuracy of coronavirus tests decreases. Researchers typically use 40 to 45 cycles of amplification.

There are some explanations for the positive result obtained. The first was that there was indeed a very small amount of SARS-CoV-2 virus particles in the effluent. Second, the sample was inadvertently contaminated with SARS-CoV-2 particles in the laboratory during the test. This is sometimes the case in laboratories that treat the virus on a regular basis: it is very difficult to prevent extremely small particles of the virus from reaching where it is not needed and contaminating other samples.

There is another explanation: The sample contains other RNA or DNA particles that are so similar to RdRp that a positive result was obtained during 39 amplification cycles.

Additional studies are needed to confirm that the wastewater analyzed by the scientists actually contained SARS-CoV-2 particles, and these important findings should be replicated by an independent laboratory, The Conversation reports.

The evaluation should be done with caution.

An interesting thing about the study findings is that they do not match the epidemiological data on the virus. The study authors provide no evidence of an increase in the number of patients with respiratory diseases in and around Barcelona in the last year after the sampling date.

Furthermore, the SARS-CoV-2 virus, at least in its current form, is known to be highly contagious. Therefore, if the result is really positive, it can be concluded that the virus was sufficiently widespread among the population if its particles were detected in an 800 ml sample of wastewater, but not to the point nine months after the emergency, even without any virus control measures.

Therefore, in the absence of additional research results, the conclusions of this study should be evaluated with great caution, The Conversation emphasizes.

The case of the Netherlands

The first report that SARS-CoV-2 was detected in wastewater came from the Netherlands in late March.

March 5 At the Amersfoort sewage treatment plant, researchers found genetic material for the coronavirus, although no cases of the disease were reported at the time, in a city about 50 km southeast of Amsterdam.

The Netherlands confirmed its first case of COVID-19 on February 27. and found that a few days later, the disease was infected by health professionals in the southern part of the country, a sign that it was beginning to spread in the community.

“It is important to collect information on the appearance of this new virus in wastewater to understand whether there is a risk to wastewater workers and to determine whether monitoring of wastewater could serve to track the circulation of SARS-CoV-2 in our communities, “said Nieuwegein, chief of the NW microbiologist Gertjan Medema with other authors. “This could complement current clinical care, which only applies to COVID-19 patients with the most severe symptoms.”

Wastewater monitoring is a well-known method of tracking poliovirus and antibiotic-resistant bacteria, as well as the use of illegal and prescription drugs.

Monitoring of wastewater could serve as an early warning of the appearance of COVID-19 in cities, Dutch researchers say.

“The fact that the virus was detected in sewers, even when the prevalence of COVID-19 is low, suggests that wastewater monitoring may be a sensitive tool to monitor the circulation of the virus in the population,” they point out.

Italian study: coronavirus was already in the country in December

The new coronavirus in two large cities in northern Italy was already in December, two months before the country’s first case of coronavirus infection COVID-19, according to a wastewater study by the National Institute of Health ISS. The researchers reported this in mid-June.

The researchers found genetic traces of the COVID-19 SARS-CoV-2 virus in sewage samples, which were collected in Milan and Turin late last year and in Bologna in January, according to an ISS statement seen on Friday by the AFP news agency.

The first known domestic case of COVID-19 in Italy was recorded in mid-February.

The results “will help to better understand the start of virus circulation in Italy,” says the ISS.

It is also added that “systematic international data corroborates” and the importance of the samples for the study.

Italy was the first European country to be affected by a coronavirus and the first in the world to introduce quarantine throughout the state.

The first known case (excluding a couple of tourists from China) is a patient from the Codonjo region in Lombardy. On February 21, the country’s authorities declared the city a red zone and ordered its closure.

Soon nine other cities in the Lombardy and Veneto regions followed suit. In early March, the quarantine spread across the country.

In Italy, the coronavirus killed more than 34,000 people. 500 people

ISS water quality expert Giuseppina La Rosa, along with her team, analyzed 40 wastewater samples from October 2019 to February 2020. The results, confirmed in two different laboratories in two different ways, revealed that SARS-Cov-2 was detected in samples taken in Milan and Turin on December 18, 2019 and in Bologna on January 29, 2020.

The responses to the samples from October and November 2019 were negative, which means that at that time the virus had not yet reached Italy, explains G. La Rosa.

Since many coronavirus patients experienced mild symptoms or no symptoms, water tests can be an effective means of detecting the virus before the first cases are clinically confirmed in areas where an outbreak has not yet occurred.

According to the ISS, they have already asked the country’s Ministry of Health to coordinate the periodic testing of water samples in sewers before the wastewater reaches the treatment plants, as “it is a reliable means of detecting and monitoring the circulation of viruses in different areas as quickly as possible. “

A pilot project for such research is planned to be launched in July in tourist centers, and the country is expected to implement a national wastewater monitoring system by fall.

China reported the outbreak to the WHO on December 31. On January 3, the country contacted the U.S. Centers for Disease Control and Prevention (CDC), and on January 8, it publicly announced that the pathogen was a new coronavirus.
In March, the South China Morning Post newspaper, citing data provided by the Chinese government, reported that the first case of new coronavirus infection in China had been clarified in November last year.

According to the data provided, the first case of infection was detected on November 17 in a 55-year-old resident of Hubei province.

From that day on, doctors diagnosed one to five new cases per day.

There were already 27 people infected on December 15 and 60 on December 20. According to representatives of the medical community, Chinese doctors did not realize they were facing a new infectious disease until the end of December.

On December 27, 2019, a doctor from Hubei province informed Chinese authorities that the cause of the disease was a new type of coronavirus. By then, 180 people infected with the virus had already been registered, but doctors were unaware of all cases.

As of December 31, 2019, there were already 266 people infected with coronavirus, and as of January 1, 2020 – 381.