The topic that was chosen for this computer-modeling project is the statistical forecasting of the AIDS/HIV virus. The topic was chosen due to the fact that the AIDS/HIV epidemic is currently a very large threat facing the world today. Cases of this disease are found all over the world. This computer program is designed to model a population that is statistically representative of the population of the United States. The populationís starting size is the same as the United Statesí, as well as contact rates (the chance that an infected individual will infect another), and age distribution.
After inputting these beginning variables, the program runs them through a modified version of the Susceptible-Infected (SI) model. The SI model employs an equation to predict the spread of the infected (people with the disease) and susceptible (people able to become infected) portions of a population, and the relation between them. This equation, however, was too simple to accurately model the spread of a disease as complex as AIDS/HIV. Due to itís inability to model many non-static variables (changing population, changing death rate, the randomness of the real world) the model was extensively modified in this computer program. The modified computer program has a birth and a death rate, and changes the contact rate depending upon the percentage of the population infected with the disease. The program also keeps track of the ages of the people in the population, and changes their contact rates based on which age group each member of the population is in. Another portion of the population, the unsusceptible, are also taken into account in the program.
After observing the results and predictions output by the program it was noticed that the population modeled did not die out due to the disease, but was affected in a detrimental manner. The program was also able to show that even in the event of a cure or vaccine being found for the disease, the population would still be negatively affected for several years afterwards. The effectiveness of the cure developed is not as important as when the cure is discovered. Also using an immunization to treat the disease is much more effective than using a cure.