[Development of a factual model for the dynamics of the transmission of infection by the human immunodeficiency virus: an example for animal epidemiology].

In order to simulate the spreading mechanism of human immunodeficiency virus (HIV), a factual approach was developed given the ease of incorporating new knowledge and taking into account the variability of a large number of sociological, biological and demographic factors, and also on account of the dynamics of the relational network of individuals. By way of example, the model was applied to data concerning homosexuals in San Francisco (United States of America) between 1980 and 1987, which enabled an evaluation to be made of the probability of HIV transmission from each partner, using two hypotheses about the evolution of contagiousness of an infected individual during the incubation period. An analysis of the sensitivity of the model revealed certain factors which had a strong influence on the growth of the epidemic. Application of this technique to the entire population of France is planned.