0 ▁had ▁been ▁hospital ised ▁and ▁ 1 1 , 6 9 0 ▁people ▁had ▁died ▁( including ▁ 1 , 1 8 0 ▁children ) ▁due ▁to ▁sw ine ▁flu ▁from ▁April ▁through ▁to ▁mid - J anu ary . ▁ ▁Initial ▁cases ▁The ▁Cent ers ▁for ▁D ise ase ▁Control ▁and ▁Pre vention ▁( CD C ) ▁identified ▁the ▁first ▁two ▁A / 0 9 ( H 1 N 1 ) ▁sw ine ▁flu ▁cases ▁in ▁California ▁on ▁April ▁ 1 7 , ▁ 2 0 0 9 , ▁via ▁the ▁Border ▁In fect ious ▁D ise ase ▁Program , ▁for ▁a ▁San ▁Diego ▁County ▁child , ▁and ▁a ▁naval ▁research ▁facility ▁studying ▁a ▁special ▁di agnostic ▁test , ▁where ▁influen za ▁sample ▁from ▁the ▁child ▁from ▁Imperial ▁County ▁was ▁tested . ▁By ▁April ▁ 2 1 , ▁en hanced ▁surve ill ance ▁was ▁established ▁to ▁search ▁for ▁additional ▁cases ▁in ▁both ▁California ▁and ▁Texas ▁and ▁the ▁CD C ▁determined ▁that ▁the ▁virus ▁stra in ▁was ▁gen et ically ▁similar ▁to ▁the ▁previously ▁known ▁A ( H 1 N 1 ) ▁sw ine ▁flu ▁circul ating ▁among ▁p igs ▁in ▁the ▁United ▁States ▁since ▁about ▁ 1 9 9 9 . ▁ ▁It ▁was ▁established ▁that ▁the ▁virus ▁was ▁a ▁combination ▁of ▁human , ▁North ▁American ▁sw ine , ▁and ▁E uras ian ▁sw ine ▁influen za ▁vir uses ; ▁the ▁vir uses ▁from ▁the ▁initial ▁two ▁Californ ian ▁cases ▁were ▁also ▁noted ▁to ▁be ▁resist ant ▁to ▁am ant ad