Bifurcations from steady state to oscillatory behavior can be associated with an increased number of infection cases, particularly if chaotic oscillations occur, as in previous dengue models (Billings et al. 2007; Bianco et al. 2009 ). Our results suggest that if control strategies in one region are able to generate enough asymmetry, this could lead to a stabilization of the outbreaks, which would have a positive effect on adjacent regions. Asymmetry could be generated in the effective contact rate by mosquito control, which could include reducing mosquito breeding sites (Slosek 1986) , or through new genetic controls which are under development (Barbazan et al. 2008) . Asymmetry in the birth rate could be generated by lowering the effective birth rate through vaccination of new susceptibles once a vaccine is available. However, because the bifurcation point saturates rather than increasing indefinitely as asymmetry increases, such a strategy would be successful only if the epidemic parameters in the real system are moderately close to the bifurcation. (Extreme asymmetry may even be destabilizing, so this strategy works best locally when the asymmetry is not too strong.) Real systems exhibiting oscillatory behavior may already be well into an unstable region of parameters. For such systems, our suggested control strategy may not apply since asymmetry between adjacent regions is already likely, thus reducing that impact that an increase in the asymmetry could have. On the other hand, in the case of dengue fever a recent study (Cummings et al. 2009 ) has highlighted a decreasing trend in both the force of infection and birth and death rates in the population of Thailand during a time span of about 30 years. This phenomenon could potentially drive the system closer to the bifurcation point and make it more amenable to control.