ABSTRACT
Attheendofthe1960s,inresponsetohealthdepartmentrequests, westartedtoengageinecoenvironmentalstudiestodeterminethe causesoftwoendemicdiseasesofhumans,Keshandisease(KD)and Kaschin-Beckdisease(KBD).Theformerisanendemiccardiomyopathy, thelatteranendemicosteoarthrosis.Sincethen,ourinvestigationand samplecollectionhaveextendedtoeveryprovinceofChina,except TaiwanProvince,andhavecoveredthemaintypesofgeographical environmentsinChina.Thedistributionofbothendemicdiseaseshas beenfoundtorelatetosomespecialcharacteristicsofthegeographical environment,especiallysoilcharacteristics.Thetwodiseasesaredistributedmainlyinadistinctwidebelt,usuallyreferredtoasthedisease belt,runningfromthenortheasttosouthwestofChinaandlocatedinthe middletransitionbeltfromthesoutheastcoasttothenorthwestinland region(Figures1and2).Thebeltismainlycharacterizedbytemperature forestandforest-steppesoilsthatbelongtothebrowndrabsoil(earth) series[1,2].
