Figure 1 illustrates the structure of the model.People flow from a Susceptible Population after invasion by HIV and become members of the HIV population capable of infecting other susceptibles.Then, infected people either move into a state of(i) clinical AIDS ( governed by the Symptom Emergence Ratio, SER) or into one of several other states(ii) die from other unrelated causes(iii) retire altogether from sexual activity on account of their age(iv) retire altogether from sexual intercourse as a reaction to knowledge of their condition(v) acquire a medically non-infectious stateAll these states render the host non-infectious since we assume that patients with clinical AIDS will no longer be sexually active.