Rhys Williams is the only starter from the first Test squad who has been ruled out completely by the bug and will be replaced at full back by Gavin Henson, who moves from the centre
Tom Shanklin, a second half replacement for Williams in Tucuman, starts in the centre with Dafydd Jones coming in at blindside flanker in place of Jason Forster.
Wales captain Colin Charvis moves to openside flanker to accommodate Jones' recall, with Forster leading an advance party which departed for South Africa yesterday (Tuesday) in preparation for the final match of the tour, against the Springboks in Pretoria on 26 June.
Mefin Davies, who is another to be affected by illness, moves to the bench and is replaced at hooker by Huw Bennett.
Nicky Robinson has been called in at fly-half for tactical reasons in place of Ceri Sweeney who moves to the bench.
Another change comes on the replacements bench, with the uncapped Barry Davies wearing the Wales tracksuit for the first time in a Test and looking for his first cap whilst providing cover for Henson.
'Gavin (Henson) is a talented player and he filled in capably for Rhys at full back in the first Test and we are looking for him to do so again,' said Ruddock.
'He is no stranger to the position and has played there before at both club and regional levels and this also gives Tom (Shanklin) a deserved start at centre. Tom is a top quality international centre and it is a testimony to the strength of our squad that we have someone of his calibre to come into the side.
'With Gareth Thomas and Kevin Morgan not making the tour through injury and now Rhys falling ill, you may say we have had little luck with full backs recently. But the squad is rich with talented backs and we have also brought in Barry Davies - who has performed consistently well for the Scarlets in that position - to provide cover from the bench.
'Dafydd Jones is deserving of a chance to impress and he slots into his natural position on the blindside. The change at hooker is mainly due to Mefin's illness and Nicky Robinson has come into the side for tactical reasons.'
Wales: Gavin Henson (Ospreys); Hal Luscombe (Dragons), Sonny Parker (Ospreys), Tom Shanklin (Blues), Shane Williams (Ospreys); Nicky Robinson (Blues), Dwayne Peel (Scarlets); Duncan Jones (Ospreys), Huw Bennett (Ospreys), Adam Jones (Ospreys), Brent Cockbain (Ospreys), Gareth Llewellyn (Unattached), Dafydd Jones (Scarlets), Colin Charvis (Newcastle Falcons, Captain), Michael Owen (Dragons) Replacements: Mefin Davies (Unattached), Gethin Jenkins (Blues), Darren Morris (Leicester Tigers), Jonathan Thomas (Ospreys), Michael Phillips (Scarlets), Ceri Sweeney (Dragons) , Barry Davies (Scarlets)
Argentina: H Senillosa; J Piossek, J Orengo, M Contepomi, L Borges; F Contepomi, N Miranda; R Roncero, F Mendez, O Hasan, I Lobbe, P Albacete, M Durand, L Ostiglia, G Longo (capt).
Replacements: M Ledesma, E Guinazu, P Bouza, M Shusterman, M Albina, J Miranda, F Aramburu.