How Long Coronavirus stays Inside Human Body ?
Does coronavirus linger in the body?
WHY IN NEWS:
What we know about how viruses in general hang on in the brain and testicles.
SYLLABUS COVERED: GS 3 : Science : Diseases
For PRELIMS understand the chronic infections , causes and the concept of immune privileged sites.
For MAINS how does a Virus become Latent Infection ? Let us dive in !
WHAT IS A CHRONIC OR PERSISTENT VIRAL INFECTION?
- In many cases the reproduction rate of parasites is at low levels.
- Frequently these infections occur in a so-called immune privileged site.
WHAT IS AN IMMUNE PRIVILEGED SITE?
There are a few places in the body that are less accessible to the immune system.
- It is advantage of having an immune privileged region is that it protects a site like the brain, for example, from being damaged.
- An immune privileged site not only is difficult for the immune system to enter, it also limits proteins that increase inflammation.
- It can also damage an organ such as the eye, brain or testes.
- The result is an uneasy truce where inflammation is limited but infection continues to fester.
A LATENT INFECTION VERSUS A PERSISTENT VIRAL INFECTION
- In a latent virus, the entire viral genome is present and infectious virus can be produced if latency ends and the infections becomes active.
- The latent virus may integrate into the human genome as a self-replicating piece of DNA called an episome.
- This can occur months to decades after the initial infection.
- To be infected with a virus capable of producing a latent infection is to be infected for the rest of your life.
- The immune system cannot detect this cell as being infected.
Latent infection (left) is when a cell is infected and the virus has inserted its genetic code into our human DNA.
HOW DOES A VIRUS BECOME A LATENT INFECTION?
- Herpes viruses are by far the most common viral infections that establish latency.
- This is a large family of viruses whose genetic material, or genome, is encoded by DNA (and not RNA such as the new coronavirus).
- Retroviruses such as HIV, which causes AIDS, can insert a copy of their genome into the human DNA that is part of the human genome.
- There the virus can exist in a latent state indefinitely in the infected humans.
- Viruses that establish latency in humans are difficult or impossible for the immune system to eradicate.
- That is because during latency there can be little or no viral protein production in the infected cell.
- This makes the infection invisible to the immune system.