Figure 2.

Relation of malaria intensity measures. In A, age-dependent parasite prevalence rates grouped into the 4 traditional endemic transmission regions with human measures of intensity show a peak in young children. Large reductions in mosquito transmission measures can still sustain high parasite prevalences. Parasite prevalence rates decrease little with 10-fold decreases in entomologic inoculation rates (EIRs) (B) and almost 100-fold decreases in the basic reproductive ratio (R₀) (C). In D, the rates of seropositivity to malaria antigens quickly saturate to near 100% at both prevalence near 25% with low EIR and R₀ less than 10. In E, the less used measure of intensity associating infant malaria rates is useful in hyperendemic and holoendemic settings with prevalence over 50%.