The Geographical Changes Of West And East Han Dynasty About Exogenous Febrile Disease

From Emperor Hanwu to the early eastern Han dynasty,febrile disease arises in the northwest region of Han dynasty. In Juyan,people had found this disesse for many times. Juyan belongs to Zhangye prefecture of han dynasty,and now it lies in the desert of Inner Mongolia.In the time of han dynasty,the Juyan Lake was better than today,people opened up wasteland around this lake.Into the eastern han dynasty,Juyan frontier fortress declined in political and military status. Because of the worse natural environment,wasteland was unsustainable.Finally Juyan frontier fortress came to an end.Then the local people bagan migrating to the south, which created population condition for the spread of exogenous febrile disease.Now,Juyan area belongs to temperate desert region which have temperate continental climate.The lack of rain throughout the year.Summer is dry, winter is cold.During the han dynasty,this place was a typical mixed farming area.Compared with modern,the climate was warm and wet.But compared with the central plains,the climate characteristics is cold winter,hot summer and little precipitation.Combine official history with bamboo and wooden slips,we find that the mid western han dynasty to the eastern han dynasty indeed has a tendency to become cold climate.The tendency is cold-warm-cold between the middle western Han and early estern Han dynasty.The historical climate change during the period of western Han and estern Han dynasty created a climate conditions forthe spread of exogenous febrile disease.Mesozoic-cenozoic region of Inner Mongolia,which Juyan frontier fortress belonged to in Han dynansty,the living environment is extremely bad and soil e-xtremely short of available zinc.In Han dynansty,the available zinc is more than now,but there is no qualitative leap.The lack of soli available zinc results in the decline of the immune system in people, made them become the suscepti-ble populations of exogenous febrile disease.Slips unearthed in the north west have showen some records about febrile disease and the relative prescription.By analyzing these slips, from the symptoms of febrile disease, infectious and epidemic regularity, the febrile disease in Han dynastyis modern influenza.The resons why febrile disease spread in northwest frontier fortress of Han dynasty are about cold climate,hot summer,little rain,sandy survival environment, serious lack of soil available zinc, coupled with poor diet condition and labor intensity has also increased the northwest frontier fortress nonlocal defensibly stroke outbreak of febrile disease, namely the occurrence of influenza.Further, in the middle of the eastern Han dynasty, because of the climate dry cooling frontier population influx, fighting, burial system,these reasons eventually lead to the outbreak of exogenous febrile disease in central plains during the late eastern Han dynasty.