The Cause of the Disease

The definition of disease is an abnormal function in a part of our body that is cause by trauma, infectious agents, hereditary conditions or environmental factors.

AIDS is cause by an infectious agent known as the Human Immunodiffiency Virus (HIV).

• HIV is a retrovirus meaning that its genetic information flows from RNA→DNA instead of DNA→RNA as is seen in most viruses.
• It is believed to have been transmitted from chimpanzees to humans in the late 1800s/early 1990s. SIV is the chimpanzee's equivalent to HIV.

Once the virus enters the body it begins to attack the immune system.

• First the virus enters the human body through some bodily fluid such as blood, semen, or vaginal fluid.
• Once inside HIV will then infect CD4/Helper T4 cells, macrophages and antigen presenting cells, which are all cells of the immune system which is responsible for defending the body against micro-organisms- such as viruses, bacteria, fungi, and protozoa

Once HIV enters the cells it causes can cause the cell to die and therefore depleting the immune system in three different ways:

1. By replicating inside the Helper T4 cell it slowly kills the cell by the new HIV budding out form the Helper T4 cell. This diagram shows the process through which HIV replicates and then buds out resulting in eventual cell death.


2. When HIV get inside the cell it induces apoptosis(programmed cell death)
3. Last thing HIV can do is induce syncytia- which is when many cells both healthy and infected form a conglomeration. These cells then become inactive and con no longer function properly.

The fact that HIV attacks specifically your Helper T4 is very detrimental to your immune system and your immune response because Helper T4 cells are responsible for activating other cells of you immune system such and B cells and Killer T8 cells when something foreign is present inside the body.

• B cells are important because the make and secrete antibodies that bind to antigens (viruses, bacteria, etc.)
• Killer T8 cells are important because they are responsible for killing virally infected cells to prevent them from replicating.

1. Killing Helper T4 cells
2. Helper T cells do not activate B cells or Killer T8 cells
3. Body is left defenseless against micro-organisms and rare diseases known as opportunistic infections.