It is now widely accepted that Sars-CoV-2 does not only strain the lungs of many infected individuals. Coronavirus manifests itself in many other organs. First researchers and doctors noticed traces in the kidney, then the liver was added, followed by the heart. Another organ came into focus in the middle of the year: the brain. However, the relationship between viral entry into the body and the central nervous system is still a mystery to researchers.
However, as the pandemic progresses, there are more and more indications that the virus is affecting the brains of infected people. Pathologists around the world find traces of viruses in the brains of the deceased. A growing number of infected patients report neurological symptoms such as headaches, dizziness, psychological problems, memory loss ̵
Ways of coronavirus in the body: infection or inflammation?
But what exactly happens in the body, how does Sars-CoV-2 get into the brain? It has been proven that the virus enters body cells mainly via so-called ACE-2 receptors (proteins). Depending on how many of them are present in the organ tissue, the virus also manifests itself there. So far, however, researchers are not sure where in the body and in what density. To date, it is also unclear whether the virus itself attacks the brain or whether the neurological symptoms are a result of the immune system being overstimulated by the infection.
It is important to find out, say immunobiologists from the Yale School of Medicine. Especially in light of the fact that an idea is currently emerging about the long-term consequential damage that a Covid 19 infection can have. After all: In various experiments, American researchers have now for the first time found concrete evidence that neurological symptoms associated with Covid-19 are associated with a direct viral invasion of the central nervous system and that Sars-CoV-2 can directly infect nerve cells. This is evident from a study that has not yet been evaluated, which was published on the preprint server Biorxiv in early September.
Information about brain damage only from the clinic
“In particular, our experiments show that the brain is a site of high replication potential for Sars-CoV-2,” the researchers write. It also attacks neighboring cells – much more aggressively than other previously known infectious diseases such as Zika. They used three methods for their results: They infected mice and human organoids (an organ-like microstructure with stem cells) with the virus. They also examined people who had died of or with the coronavirus. U.S. researchers from the University of San California came to similar results, which were also published in preprint, in late May.
The pathways of the virus in the body have not yet been examined in detail due to insufficient studies. The data situation also does not reveal the extent to which people who are less seriously ill but who are still infected with Sars-CoV-2 may be affected. So far, only individual studies have been performed on hospital patients.
In a study of British patient data, for example, the researchers calculated the probability of hospitalization and thus more seriously ill Covid 19 patients develop serious neurological complications. Of the 125 people examined in the study, 62 percent suffered brain damage – with stroke and bleeding as a result. 31 percent suffered from mental states of confusion or swelling in the brain tissue. Ten of the subjects examined developed psychosis.
Similar observations were made with about 500 hospital patients in Wuhan and Hubei, China – about half of them suffered from neurological symptoms such as dizziness, difficulty concentrating, loss of smell and taste, seizures, stroke and weakness. A study was published in mid-June in the journal “Annals of Neurology”.
Covid-19 is more than a lung disease
A report published in The Lancet in early July, given the number of patients registered worldwide with neurological disorders, does not assume a mass phenomenon. “The proportion of infections that lead to neurological diseases is likely to remain low,” the researchers predict. However, given the increasing number of cases worldwide, one can expect a high health burden and social and economic costs compared to the time before Corona.
The Robert Koch Institute has now included neurological symptoms in its profile on Sars-CoV-2. “Covid-19 can manifest itself in many ways and not only in the lungs but also in other organ systems,” writes the National Board of Health. “Headaches, dizziness and other exacerbations that suggest neuroinvasive properties of the virus are described as neurological symptoms.” As the virus is new, no clear statements can yet be made about long-term effects and consequential damage.