And if that is the case, can this explain some of the long-term symptoms of Covid-19, or is it dangerous for the infection to pass to others even after recovery ?, according to what Russia Today reported.
William Petrie, a doctor and an infectious disease scientist at the University of Virginia, who cares for infected patients and searches for “Covid-19”, reviewed what is known “today” for chronic or persistent disease.
What is a chronic or persistent viral infection?
Chronic or persistent infections last for months or even years, during which the virus is constantly produced, albeit in many cases at low levels. These infections often occur in what is called the “privileged immunity” site.
What is the distinct immune site?
There are few places in the body that are less accessible to the immune system, as it is difficult to eliminate all viral infections. These include: the central nervous system, testes and eyes.
It is believed that the evolutionary advantage of possessing a region with distinctive immunity is that it protects a site such as the brain, for example, from damage due to inflammation that results when the immune system fights infection.
Not only is it difficult for the immune system to enter a distinct immune site, but it also limits proteins that increase inflammation. The reason is that while inflammation helps kill a pathogen, it may damage an organ such as the eye, brain, or testes.
The result is an unstable truce, where the inflammation is limited but the infection continues to worsen.
Latent infection vs. continuous viral infection
There is another way in which the virus can hide in the body and reappear later.
Latent viral infection occurs when the virus is inside an infected cell, but it is inactive and does not reproduce. In the latent virus, the entire viral genome exists, and the infectious virus can be produced if the inactivity ends and the infection becomes active.
The latent virus may fuse in the human genome – such as HIV, for example – or be found in the nucleus as a self-reproducing piece of DNA, called the ring.
The latent virus can reactivate and produce infectious viruses, and this can happen months to decades after the initial infection. Perhaps the best example of this is chickenpox, which although it appears that the immune system has decimated it, can revitalize it and cause zoster herpes decades later.
Fortunately, chickenpox and herpes were now prevented by vaccination.
How does a virus become a latent infection?
Herpes viruses are the most common viral infection that establishes the underlying condition.
This is a large group of viruses whose genetic material, or genome, is encoded by DNA (not RNA like the new Corona virus). Herpes viruses also include chickenpox.
Other herpes viruses, such as Epstein Barr, can appear after lethargy.
Retroviruses are another common series of viruses, which prove to hide but with a different mechanism from herpesvirus. Retroviruses such as HIV, which causes AIDS, can insert a copy of the genome into the human DNA, which is part of the human genome.
There, the virus can be found in a latent condition indefinitely in the affected human, where the virus’s genome is copied every time the DNA is transcribed and the cell division.
During the period of inactivity or hiding, there may be little viral protein production, or none at all in the affected cell, making the infection invisible to the immune system.
Fortunately, corona viruses do not prove an underlying infection.
In one small study, the new corona virus was detected in semen in a quarter of patients during active infection, and in less than 10% of patients who appeared to have recovered.
In this study, viral RNA was detected, and it is not yet known whether RNA is still an infection or a dead virus in the semen.
The Ebola virus is completely different from SARS-C0V-2, but it is an example of the virus continuing in immune-immune sites. In some individuals, the Ebola virus survives in distinct immune sites for months after the acute disease is resolved.
Ebola survivors were recorded with persistent infection in the testes, eyes, placenta, and central nervous system.
The World Health Organization recommends that male male Ebola virus survivors examine the semen, to reveal the possibility of the virus every 3 months. They also suggest that couples refrain from having sex for 12 months after recovery, or until their semen test becomes negative for Ebola twice.
We need to know more about new infections with the Coronavirus, before considering similar recommendations.
Coveid-19 recovery is delayed in many individuals, with symptoms including coughing, shortness of breath and fatigue. It seems unlikely that these symptoms are due to the continued presence of the virus, as the symptoms do not come from sites with immune privileges.
Where can the new coronavirus continue after recovery from “Covid-19”?
Other sites where the Coronavirus has been detected include the placenta, intestine, blood and, of course, the respiratory system. In women who develop “Covid-19” during pregnancy, the placenta defects the blood vessels of the mother feeding the placenta.
However, the importance of this to the health of the fetus has not been determined.
The new corona virus can also infect the fetus by the placenta. Finally, the virus is present in the blood, nasal cavity and palate, for up to a month or more after infection.
Growing evidence suggests that the corona virus can infect distinct immune sites, and from there, it produces a persistent chronic infection – but not latent.
It is too early to know the extent of the impact of these ongoing infections on the health of an individual such as a pregnant mother, for example, or the extent of their contribution to the spread of “Covid-19”.
And like many things in this epidemic, what is unknown today may be known tomorrow, so stay tuned and take the necessary precautions, so as not to become infected, or worse, to spread it to others.