A STOCHASTIC-MODEL OF THE HIV EPIDEMIC INVOLVING BOTH SEXUAL CONTACT AND IV DRUG-USE

In this paper we develop a stochastic model for the HIV epidemic invol ving both sexual contact and IV drug use by taking into account the dy namic of the HIV epidemic. The model is formulated in terms of the cha in multi-nomial model which provides a mechanism by means of which one may derive the moments of the numbers of S people, L people, I people and A people. By using the model we show by Monte Carlo studies that the randomness of the number of different partners per unit time seem to have little effects on the HIV epidemic if the expected number of d ifferent partners per unit time is not very small (say greater-than-or -equal-to 0.5). However, the numerical results indicate clearly that i n almost all the cases the results of the deterministic model provide poor approximation to the corresponding expected numbers of the stocha stic model.