An epidemiological population model is proposed to assess the impact of pro
tection and/or treatment strategies applied to HIV infection. Sex-education
campaigns are the available protection strategy, and drug (or association
of drugs) administration is the treatment strategy considered. In this mode
l we assumed recruitment and differential mortality rates for the homosexua
l population. In addition to the classical threshold contact rate related t
o the establishment of the disease, we obtained a threshold input rate.