The distribution of hereditary erythrocytic disorders associated with malaria, in a lowland area of Nepal: a micro-epidemiological study.

Among four ethnic groups in a lowland area of Nepal, the prevalences of abnormal haemoglobin, thalassaemia, glucose-6-phosphate-dehydrogenase (G6PD) deficiency, hereditary South-east Asian ovalocytosis (SAO) and Duffy blood-group antigen Fy/Fy were determined and related to each group's habitat. The group that has lived for many decades in a malaria-endemic lowland area, the Danuwar, was found to have a high prevalence of alpha+-thalassaemia (79.4%) and low prevalences of haemoglobin E and G6PD deficiency. Much lower prevalences of alpha+-thalassaemia were observed in the Newar (20.5%), Parbate (16.5%) and Tamang (8.8%), who, until the 1950s, all spent their hot-season nights in malaria-free areas at higher altitudes. No subjects with any other identified abnormal haemoglobin, beta-thalassaemia, SAO or Fy/Fy were detected.