e . ▁Using ▁substr ate ▁specific ity ▁studies ▁and ▁in hib itor ▁analysis , ▁it ▁was ▁found ▁that ▁the ▁pl as me ps ins ▁for ▁P . ▁mal aria e ▁and ▁P . ▁viv ax ▁showed ▁less ▁specific ity ▁than ▁that ▁for ▁P . ▁fal ci par um . ▁Unfortunately , ▁this ▁means ▁that ▁the ▁development ▁of ▁a ▁select ive ▁in hib itor ▁for ▁P . ▁mal aria e ▁may ▁prove ▁more ▁challeng ing ▁than ▁the ▁development ▁of ▁one ▁for ▁P . ▁fal ci par um . ▁Another ▁study ▁by ▁Bruce ▁et ▁al . ▁presented ▁evidence ▁that ▁there ▁may ▁be ▁regular ▁gen etic ▁exchange ▁within ▁P . ▁mal aria e ▁populations . ▁Six ▁polym orph ic ▁gen etic ▁markers ▁from ▁P . ▁mal aria e ▁were ▁isolated ▁and ▁analyz ed ▁in ▁ 7 0 ▁samples ▁of ▁naturally ▁acquired ▁P . ▁mal aria e ▁in fe ctions ▁from ▁different ▁parts ▁of ▁the ▁world . ▁The ▁data ▁showed ▁a ▁high ▁level ▁of ▁multi - gen ot yp ic ▁carriage ▁in ▁humans . ▁ ▁Both ▁of ▁these ▁experiments ▁illustrate ▁that ▁development ▁of ▁v acc ine ▁options ▁will ▁prove ▁challeng ing , ▁if ▁not ▁impossible . ▁Dr . ▁William ▁Collins ▁doub ts ▁that ▁anyone ▁is ▁currently ▁looking ▁for ▁possible ▁v acc ines ▁for ▁P . ▁mal aria e ▁and ▁given ▁the ▁complexity ▁of ▁the ▁par as ite ▁it ▁can ▁be ▁infer red ▁why . ▁He ▁states ▁that ▁very ▁few ▁studies ▁are ▁conducted ▁with ▁this ▁par as ite , ▁perhaps ▁as ▁a ▁result ▁of ▁its ▁perce ived ▁low