Table 1.
Equations for the initial susceptible populations at seroprevalence pi.
Figure 1.
Change in monthly mean temperatures in Singapore.
Figure 2.
Change in the threshold mosquito density in Singapore from the 1980s to the 2000s.
Simulation 1: Effect of only temperature change with single serotype at seroprevalence 0%. Simulation 2: Effects of temperature and the fluctuation of population immunity with a single serotype. Simulation 3: Effects of temperature and population immunity with 4 serotypes. The seroprevalence of dengue antibodies in the Singaporean population was estimated to be 70% in 1980, 60% in 1990, and 50% in 2000 [26]. Threshold MPP is the number of female mosquitoes per person that causes an epidemic (10% increase of seroprevalence). A lower threshold MPP indicates a higher probability of epidemics.
Figure 3.
Threshold mosquito density at various population immunity levels and numbers of serotypes.
Simulations were conducted at a constant temperature of 25°C. Threshold MPP is the number of female mosquitoes per person that causes an epidemic (10% increase of seroprevalence). A lower threshold MPP indicates a higher probability of epidemics.
Figure 4.
Comparison of the threshold mosquito density resulting in R0 = 1.
Dark green bars represent m calculated by equation 2 [16] and light green bars represent our result (MPPR0 = 1).
Table 2.
Result of uncertainty analysis.
Figure 5.
Change in the threshold mosquito density.
The effect of a 5% change in each parameter after univariate sensitivity analysis.