RESUMEN
Morbidity and mortality patterns, health care practices, and health care beliefs were assessed over three seasons in Pwo and Sgaw Karen preschool children living in the highlands of northwest Thailand. The sample consisted of all preschool children from 77 Pwo and 71 Sgaw households. Although the Pwo and Sgaw Karen residing in the highlands of northwest Thailand live in isolated villages in the same ecozone, utilize similar technologies, have similar access to health facilities, and maintain a certain level of sociocultural homogeneity through their identification as Karen, Pwo preschool children exhibit significantly higher levels of morbidity and mortality than their Sgaw counterparts. It is argued that these differences in morbidity and mortality are primarily the function of historical patterns which resulted in an earlier contact of the Sgaw with modem societies and particularly with an earlier exposure to western health care.