 <unk> vegetation ( such as that of tropical rainforests ) and urban habitats are not ideal for the establishment of the human transmission cycle . However , in regions where the sylvatic habitat and its fauna are <unk> by economic exploitation and human habitation , such as in newly <unk> areas , <unk> palm culture areas , and some parts of the Amazon region , a human transmission cycle may develop as the insects search for new food sources . 
