Figure 2.

Seasonal index and monthly incidence of Plasmodium falciparum and Plasmodium vivax malaria in Hainan, China, 1995–2008. Relatively high malaria incidence was observed during May–October, during which 69.8% of P. falciparum malaria cases and 67.0% of P. vivax malaria cases were reported. The cumulative monthly incidence of these two types of malaria reached their peaks in August (P. falciparum malaria, 16.20/100,000; P. vivax malaria, 48.78/100,000). The highest seasonal index was 1.75 for P. falciparum malaria and 1.61 for P. vivax malaria, and the lowest was 0.40 for both types of malaria.