at the same time , a combination of factors , in particular the war-time sojourn of masses of troops from africa , already infected by filarial diseases , in the southwestern coastal areas triggered off an unexpected spread of the urban type out of its early `` '' bridge-heads '' '' in galle and matara towns to invade the southwest coastal areas , and , later on , supported by increased population mobility , to advance further inland too .
C0001737
africa
C0040363
,