The All Blacks are on high alert for more cases of mumps after Ardie Savea became the third player to be struck by the highly contagious infection.
Loose-forward Savea has been put in isolation at the team's hotel in Cardiff and will not be considered for the match against Wales on Sunday morning (NZ time).
Wing Rieko Ioane contracted the illness earlier in the tour but recovered to play a part until being ruled out of this weekend's clash with Wales by an injury he picked up during the 22-17 victory over Scotland last weekend.
Utility back Jack Goodhue also picked up the illness before the squad departed New Zealand for the tour, forcing his departure to the UK to be delayed.
All Blacks assistant coach Ian Foster said Savea had a "mild case" of the mumps.
"He is in his room and has been in isolation. He was fully vaccinated as a kid, but he clearly has something.
"He is actually recovering pretty quickly. Are we worried about it (spreading)? No, we are not. Have we taken precautions? Yes we have.
"Ardie must have been in pretty close proximity to Rieko at some point. It caught us on the hop a little bit but we are satisfied with way the Doc [team doctor Tony Page] has reacted. He's done a great job in isolating it."
Asked about the condition of other members of the New Zealand squad, Foster said they were not showing any warning signs and added the management group were taking the situation "really seriously".
Give the whole team the jab - doctor
The All Blacks should consider immunising the whole team, Auckland University lecturer in vaccinology Helen Petousis-Harris said.
She said mumps immunity could diminish after vaccination.
She said some people were not fully covered if they have only had one of two childhood jabs.
"One of the options when you've got an outbreak situation and you have seen people who are fully vaccinated getting the disease," Dr Petousis-Harris said.
"And you also have others around who aren't vaccinated or don't know [if they are]. The simplest solution is to go out and just get a dose of vaccine."