▁from ▁a ▁sl oth ▁( B rad yp us ▁tr id act yl us ) ▁and ▁a ▁pool ▁of ▁O ch ler ot atus ▁( O ch ler ot atus ) ▁ser r atus ▁mos qu ito es ▁in ▁Brazil . ▁The ▁virus ▁is ▁considered ▁a ▁public ▁health ▁threat ▁in ▁tropical ▁and ▁subt rop ical ▁areas ▁of ▁Central ▁and ▁South ▁America , ▁with ▁over ▁half ▁million ▁inf ected ▁people ▁as ▁of ▁ 2 0 0 5 . ▁O RO V ▁is ▁considered ▁to ▁be ▁an ▁ar b ov irus ▁due ▁to ▁the ▁method ▁of ▁transmission ▁by ▁the ▁mos qu ito es ▁A edes ▁ser r atus ▁and ▁C ule x ▁qu in que fas ci atus ▁among ▁sl oth s , ▁mars up ial s , ▁prim ates , ▁and ▁birds . ▁ ▁Ep ide mic ▁S ites ▁Between ▁ 1 9 6 1 ▁and ▁ 1 9 8 0 , ▁O RO V ▁was ▁reported ▁in ▁the ▁northern ▁state ▁of ▁Par á , ▁Brazil , ▁and ▁from ▁ 1 9 8 0 ▁to ▁ 2 0 0 4 , ▁O RO V ▁had ▁spread ▁to ▁the ▁Amazon as , ▁Am ap á , ▁A cre , ▁R ond ô nia , ▁T oc ant is , ▁and ▁Mar anh ão . ▁The ▁virus ▁would ▁cause ▁O rop ou che ▁fe ver , ▁an ▁urban ▁ar b ov iral ▁disease ▁that ▁has ▁since ▁resulted ▁in ▁> 3 0 ▁ep ide m ics ▁during ▁ 1 9 6 0 – 2 0 0 9