The term virulence simply means the degree of disease causing ability of an infectious agent.
HIV is one heck of a virus that has so far defied science through its non availability of drug for permanent cure.
HIV virus just as earlier said, has high attraction for CD4 cells or T-helper cells that play major role in protecting the body system against infection.
The major reason why HIV is more attracted to the helper T cells is because the helper T cells have a surface receptor to which the HIV can bind to.
It's common to say that HIV is transmitted through sexual intercourse but do you actually know the mechanism through which this happens?
Directly, they easily enter the body system through blood to blood contact but through sexual contact, it's a different scenario.
The mucous membranes on the wall of the vagina, rectum are endowed with a lot of CD4 cells, HIV infects these cells and through this means, you get infected.
In the same vein, dendritic cells (major antigen presenting cells on skin surface that primarily capture infectious agents e.g HIV and transport them to the lymph node where other immune cells especially the T cells are activated.
The replication of the virus thus begins in the lymph nodes and during this stage, the virus is not detectable.
A virus undetectable at this point is equally untransmitable, bear this in mind.
On what basis is the virulence?
The virulence of HIV is based on its ability to invade and take over the genetic machinery of the host cell.
Generally, cells that have CD4 receptors on their surfaces are attacked by HIV.
Examples include the Dendritic cell, macrophages, monocytes and lymphocyte - T-cells.
Upon entry into the blood, with their GP120 glycoprotein spike, they lock onto the CD4 receptors on the T helper cells and in order to ensure that the attachment is stable, a co-receptor either CCR5 or CXCR4 is also engaged.
It then uses its GP41 protein to fuse its envelop with the cell wall of the T helper cell. This singular action then allows the capsid of the of the HIV to enter the T- cell.
Once inside, they take over the T cells and use their genetic machinery to produce more HIV.
Another fascinating thing about HIV is that, they are are highly evasive (that is, they have the ability of circumventing the host immune system). How on earth do they do this?
Why HIV is not curable up till date
HIV integrates itself into the DNA of human immune system cells and only replicates when the cell is stimulated to respond to an infection. These cells are called latently-infected cells.
These cells are not recognised as infected by the immune system and killed off, allowing them to persist for as long as the cell lives.
You can only regulate its replication with anti-retroviral drugs but you cannot remove it from the body.
This is the main reason why they say it has no cure. It continues to attack and damage CD4 cells until their levels are significantly low thus, leaving the bloody vulnerable to opportunistic infections.
A state regarded as Acquire immune deficiency syndrome (AIDS). Bear in mind that AIDS is the most critical stage of HIV infection and it also regarded as the stage 3.
More reason why most patients with long HIV history suffer opportunistic infections (infections as a result of weakened immune system) like Tuberculosis, herpes simplex virus 1, salmonella, toxoplasmosis, candidiasis etc
Effects of drugs
Drugs produced only target specific stages of the virus replication so as to inhibit them.
A simple block in the CCR5 or CXCR4 receptors by drugs for example, automatically inhibits infection of the CD4 cells by HIV.
A viral load above 100,000 copies/ml is tantamount to speedy reduction in the CD4 cells. Test done to detect HIV, targets the presence of the HIV antibody and the HIV P24 antigen.
In all, administration only help to reduce to viral load and consequently increase the CD4 cell counts in the patient, so as to boost the immune system in a bid to prevent opportunistic infections.
Without treatment, death as a result of AIDS is certain and inevitable. Due to advancement in science and medicine, the development of drugs has gone a long way to keep HIV patients healthy and strong.
Earlier before now, it was believed that infection with HIV is death sentence, the reverse is the case now. With anti retroviral drugs, one can still live a normal life, healthy and strong.
Haven said all the above about HIV, are the explanations enough to tag HIV and the most notorious? Let's quickly delve into the world of another harbinger of death - Cancer
