Basic models suitable to explain the epidemiology of dengue fever have previously
shown the possibility of deterministically chaotic attractors, which might explain the observed
fluctuations found in empiric outbreak data. However, the region of bifurcations and chaos require
strong enhanced infectivity on secondary infection, motivated by experimental findings of
antibody-dependent-enhancement. Including temporary cross-immunity in such models, which is
common knowledge among field researchers in dengue, we find bifurcations up to chaotic attractors
in much wider and also unexpected parameter regions of reduced infectivity on secondary
infection, realistically describing more likely hospitalization on secondary infection when the viral
load becomes high. The model shows Hopf bifurcations, symmetry breaking bifurcations of limit
cycles, coexisting isolas, and two different possible routes to chaos, via the Feigenbaum period
doubling and via torus bifurcations.