Modelling the effect of screening of unaware infectives on the spread of HIV infection

In this paper, a non-linear mathematical model is proposed and analyzed to study the effect of screening of unaware infectives on the spread of HIV/AIDS in a homogeneous population with constant immigration of susceptibles. In modeling the dynamics, the population is divided into four subclasses of HIV negatives but susceptibles, HIV positives or infectives that do not know they are infected, HIV positives that know they are infected and that of AIDS patients. Susceptibles are assumed to become infected via sexual contacts with (both types of) infectives and all infectives move with a constant rate to develop AIDS. The model is analyzed by using the stability theory of differential equations and numerical simulation. The model analysis shows that screening of unaware infectives has the effect of reducing the spread of the AIDS epidemic in a homogeneous population with migration. It is noted that the endemicity of the infection is reduced when infectives after becoming aware of their infection do not take part in sexual interaction whereas it increases in the absence of screening of unaware infectives. The model analysis has also been applied to compare the theoretical results with the known Indian HIV data. (c) 2006 Elsevier Inc. All rights reserved.