Naked Science Forum

Life Sciences => Physiology & Medicine => COVID-19 => Topic started by: Petrochemicals on 27/11/2023 12:09:31

Title: What is "long covid" and what different types are there?
Post by: Petrochemicals on 27/11/2023 12:09:31
I have met a few people who have long covid, I think they have different symptoms, so what precicely is it?
Title: Re: What is "long covid" and what different types are there?
Post by: paul cotter on 27/11/2023 13:32:47
It is a postviral syndrome that occurs long after the initial infection has been cleared. Many viral and bacterial infections can cause similar problems, not just covid.
Title: Re: What is "long covid" and what different types are there?
Post by: Petrochemicals on 27/11/2023 23:42:05
It is a postviral syndrome that occurs long after the initial infection has been cleared. Many viral and bacterial infections can cause similar problems, not just covid.
I which ways does it function as a post viral syndrome. Is it actual tissue damage, an immune response, a disfunction of the different organs?
Title: Re: What is "long covid" and what different types are there?
Post by: paul cotter on 28/11/2023 09:27:23
If I could answer some of the questions about postviral syndromes I could become quite wealthy-very little is understood. It is diagnosed based on a patient's symptoms, there is no test to do this. Look into the history of chronic fatigue syndrome. There are as many theories concerning the cause as there is in the case of ball lightning. It appears to involve subtle changes in the immune system, possibly t1/t2 lymphocyte dominance but as I said it does remain a mystery despite extensive research. It can range from relatively mild symptoms to incapacitating ones and again why this is so remains unexplained. Some patients improve over time and others do not.
Title: Re: What is "long covid" and what different types are there?
Post by: evan_au on 28/11/2023 09:39:29
Chronic Fatigue Syndrome is a well-known condition that can last for months after an infection of mononucleosis or some viruses.
- The causes are not well understood
- Some COVID patients seem to suffer something similar.
https://en.wikipedia.org/wiki/Chronic_fatigue_syndrome

COVID attacks cells via the ACE2 receptor on their surface. This receptor is involved in regulating blood pressure.
- This receptor appears on many cell types including lungs (the normal route of infection), lining of blood vessels, kidneys, and nerve-supporting cells.
- Loss of nerve-supporting cells can kill nerve cells, resulting in COVID's most distinctive symptom: Loss of taste and smell.
- If this spreads into the brain, it could be responsible for the death of brain cells - a study of patient MRIs before and after COVID showed a reduction in brain volume (faster than normal shrinkage). This could be responsible for the "brain fog" symptom which is often reported by long COVID sufferers.
- Since every organ depends on a flow of oxygen and glucose, inflammation of the blood vessels (and resulting blood clots) could damage every organ in the body (depending on where the blood clots occur), resulting in a wide array of medical conditions.

Probably, Long COVID symptoms will eventually be grouped into 5 or more clusters of symptoms - where one person may be suffering from 1 or more of these clusters.
https://en.wikipedia.org/wiki/Long_COVID

(Overlap with Paul)
Title: Re: What is "long covid" and what different types are there?
Post by: Petrochemicals on 29/11/2023 15:03:02
I notice on the wiki article there is mention of persistent viral infection, are people carriers of the virus? If so does it end up in the eyeball as with ebola? Or iis it more like chickenpox as a dormant virus all overvwith the body continually in immune response phase.
Title: Re: What is "long covid" and what different types are there?
Post by: paul cotter on 29/11/2023 17:15:49
Chickenpox and EBV(which causes mononucleosis aka glandular fever) are both members of the dna herpesviruses and initial infection leads to lifelong persistence. In the case of post EBV infection an ongoing active viral replication may be the cause of prolonged symptoms but it has not been proven, to date. In the case of other viruses that are normally cleared the possibility of a persistent infection is even more speculative. PS I made a rant about EBV and it's possible role in a multitude of chronic illnesses but nobody replied!