Many diseases are caused by germs (microorganisms) which invade the body and alter the normal body functioning. These germs differ from one another and are thus grouped as viruses, bacteria or fungi. The most devastating and difficult diseases to treat are those caused by viruses, due to their uniqueness from other microorganisms. Viruses are very small in size (minute) and have no cellular structure, little wonder, they are called infectious particles.
The most outstanding feature of viruses is their inability to grow (replicate) outside living cells and because of this, fewer drugs are available to treat viral infections. More confounding in their ability to cause diseases is a group of viruses called retroviruses and in particular, Human Immunodeficiency Virus (HIV).
So what makes HIV more confounding than other viruses?
A clearer understanding of the uniqueness of HIV can be achieved by understanding how viruses cause diseases. Viruses can only grow inside a living cell outside of which they are inactive (metabolically inert), and this is why unlike other microorganisms which invade tissue surfaces, viruses invade the cells. Following entry into a cell, a virus shuts down all the activities of the host cell, then it directs the cell to produce the materials (proteins and nucleic components) required to make new viruses (virions) during its growth.
The new (daughter) viruses then grow and mature inside the host cell and are eventually released through rupture of the cell membrane(unenveloped viruses) or by budding(enveloped viruses).Either way, both processes of release lead to the death of the host cell whereas the new viruses infect more cells and the process continues. This process is devastating considering that most drugs cannot act against germs within the cells (intracellular pathogens). The viruses can therefore hide causing more and more infections without being destroyed and the high number of cell death eventually lead to the death of the whole organism.
In the case of HIV, what distinguishes it from other viruses and makes it a monster of sorts is the type of human body cells it invades and the subsequent weakening of the body’s immune system leading to AIDS. Within the body of an infected individual, HIV is mainly present in semen, vaginal/cervical secretions and blood. It may also be present in saliva, tears, urine, breastmilk, cerebralspinal fluid and infected discharges. The virus can be transmitted from infected person to uninfected person through sexual intercourse, from mother to child during birth, blood transfusion and use of contaminated syringes and needles.
Once inside the body, HIV infects the very cells which are meant to defend the body against germs that cause diseases. Worst of all, the virus readily infects the type of cells (CD4 T-cells) which control and regulate almost the entire body’s defense system in addition to infecting other cellular components involved in the body’s defences.As was described earlier, this state of affairs leads to massive destruction of immune cells hence leaving the body vulnerable to all kinds of disease – causing organisms which in essence would not have caused any disease had the immune cells not been depleted. The depletion of the body defences continues over a long period of time and the resulting immunosuppression paves way for opportunistic infections such as pneumonia, tuberculosis, typhoid, dysentery and meningitis. These diseases further weaken the body’s immune system resulting into immunodeficiency which eventually leads to full blown AIDS.
Indeed, the devastation caused by HIV may be compared to a nation whose armed forces have been killed and so its citizens are attacked from all sides by foreign aggressors eventually leading to the demise of that nation.