eng Ansari Education and Research Society Journal of Ultra Scientist of Physical Sciences December 2009 21 3 903 908 jusps-A 1273 article Sandip Omar (sandippmar@yahoo.com) 1 Vivekananda Grmodyog P.G. College, Dibiyapur - 206 244 Auraiya (INDIA) <p style="text-align:justify">In this paper, a simple deterministic mathematical model is proposed to study the transmission of HIV/AIDS in a population with variable size structure. The model is applicable to a population of homosexual males with constant immigration rate and natural mortality rate. The model has been studied qualitatively using stability theory. It is shown that the positive non-trivial equilibrium is always locally stable but it may become globally stable under certain conditions showing that the disease becomes endemic due to constant migration of the population into the community.</p> https://www.ultrascientist.org/paper/1273/ nonlinear hiv/aids epidemic simple mass action