title: Backward bifurcation in a model for HTLV-I infection of CD4+ T cells.
abstract: Human T-cell Lymphotropic Virus Type I (HTLV-I) primarily infects CD4+ helper T cells. HTLV-I infection is clinically linked to the development of Adult T-cell Leukemia/Lymphoma and of HTLV-I Associated Myelopathy/Tropical Spastic Paraparesis, among other illnesses. HTLV-I transmission can be either horizontal through cell-to-cell contact, or vertical through mitotic division of infected CD4+ T cells. It has been observed that HTLV-I infection has a high proviral load but a low rate of proviral genetic variation. This suggests that vertical transmission through mitotic division of infected cells may play an important role. We consider and analyze a mathematical model for HTLV-I infection of CD4+ T cells that incorporates both horizontal and vertical transmission. Among interesting dynamical behaviors of the model is a backward bifurcation which raises many new challenges to effective infection control.
authors.affiliation: Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, T6G 2G1, Canada.
authors.forename: Horacio
authors.initials: H
authors.lastname: Gómez-Acevedo
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Li
mesh_terms: D000465:Algorithms; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000821:virology*; D016923:Cell Death; D049109:Cell Proliferation; D003198:Computer Simulation; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000254:growth & development*; D006801:Humans; D008954:Models, Biological