▁such ▁increase ▁would ▁suggest ▁direct ing ▁more ▁attention ▁and ▁fund ing ▁toward ▁changing ▁environmental ▁factors ▁instead ▁of ▁continu ing ▁to ▁focus ▁on ▁gen et ics . ▁ ▁Ge ographical ▁frequency ▁ ▁Africa ▁The ▁pre val ence ▁of ▁aut ism ▁in ▁Africa ▁is ▁unknown . ▁ ▁The ▁Amer icas ▁ ▁The ▁pre val ence ▁of ▁aut ism ▁in ▁the ▁Amer icas ▁overall ▁is ▁unknown . ▁ ▁Canada ▁The ▁rate ▁of ▁aut ism ▁diagn oses ▁in ▁Canada ▁was ▁ 1 ▁in ▁ 4 5 0 ▁in ▁ 2 0 0 3 . ▁However , ▁pre lim inary ▁results ▁of ▁an ▁ep ide mi ological ▁study ▁conducted ▁at ▁Montreal ▁Children ' s ▁Hospital ▁in ▁the ▁ 2 0 0 – 2 0 0 4 ▁school ▁year ▁found ▁a ▁pre val ence ▁rate ▁of ▁ 0 . 6 8 % ▁( or ▁ 1 ▁per ▁ 1 4 7 ). ▁ ▁A ▁ 2 0 0 1 ▁review ▁of ▁the ▁medical ▁research ▁conducted ▁by ▁the ▁Public ▁Health ▁Agency ▁of ▁Canada ▁concluded ▁that ▁there ▁was ▁no ▁link ▁between ▁M MR ▁v acc ine ▁and ▁either ▁infl am mat ory ▁bow el ▁disease ▁or ▁aut ism . ▁The ▁review ▁noted , ▁" An ▁increase ▁in ▁cases ▁of ▁aut ism ▁was ▁noted ▁by ▁year ▁of ▁birth ▁from ▁ 1 9 7 9 ▁to ▁ 1 9 9 2 ; ▁however , ▁no ▁increment al ▁increase ▁in ▁cases ▁was ▁observed ▁after ▁the ▁introduction ▁of ▁M MR ▁v acc ination ." ▁ ▁After ▁the ▁introduction ▁of ▁M MR , ▁" A ▁time