A two-sex model for the influence of heavy alcohol consumption on the spread of HIV/AIDS

The HIV/AIDS epidemic, one of the leading public health problems to have affected sub-Sahara Africa, is a multifaceted problem with social, behavioral and biological aspects. In the absence of a cure, behavioral change has been advocated as an intervention strategy for reversing the epidemic. Empirical studies have found heavy alcohol consumption to be a fueling factor for HIV/AIDS infection and progression. Previously [20], we formulated and analyzed a one-sex deterministic model to capture the dynamics of this deadly interaction. But, since alcohol drinking habits, consequent risky sexual practices, alcohol-induced immune suppression, etc., can be different for men and women, the primary objective of our present paper is to construct a two-sex model aimed at shedding light on how both sexes, with varying heavy alcohol consumption trends, contribute differently to the HIV/AIDS spread. Based on numerical simulations, supported by the UNAIDS epidemiological software SPECTRUM and using the available data, our study identifies heavy drinking among men and women to be a major driving force for HIV/AIDS in Botswana and sub-Sahara Africa and quantifies its hazardous outcomes in terms of increased number of active TB cases and economic burden caused by increased need for AntiRetroviral Therapy (ART). Our simulations point to the heavy-drinking habits of men as a major reason for the continuing disproportionate impact of HIV/AIDS on women in sub-Sahara Africa. Our analysis has revealed the possibility of the phenomenon of backward bifurcation. In contrast to the result in some HIV vaccination models [52], backward bifurcation in our model is not removed by replacing the corresponding standard incidence function with a mass action incidence, but is removed by merging the two susceptible classes of the same sex into one, i.e., by ignoring acquisition of, and ongoing recovery from, heavy-drinking habits among the susceptible population.