Figure 1.

Map showing the survey villages in Yongcheng city of Henan Province, People's Republic of China. Yellow dot represents the study village; Dingtang village and Zenglou village in Lizhai township belongs to high levels of historical incidence of P. vivax malaria; Renhu village and Mengzhuang village in Houling township belongs to intermediate level of historical incidence of P. vivax malaria; Wangshanzhuang village and Magutong village in Chenji township belongs to low levels of historical incidence of P. vivax malaria.