Infectious Diseases

Question 1

Describe how infection by HIV causes diseases

Answer 1

1. HIV enters the bloodstream and the primary target cells of HIV are T helper
   cells and macrophages of the immune system
2. HIV has a strong affinity for and binds to CD4 which are found on T helper
   cells and macrophages
3. T helper cells are more affected than macrophages in HIV infection
4. HIV infects the T helper cells and replication of the virus destroys the host
   cells, resulting in low T cell count
5. The macrophages may survive HIV infection because they are not lysed by the
   virus
6. When the T cell count gets very low in an affected person, the immune system
   becomes so weak such that one becomes susceptible to opportunistic
   infections
7. AIDS occurs when the infection becomes uncontrollable when associated with immunodeficiency caused by HIV infection