>>211856849
>>211856916
In season 4, Odo went through an exam to see if they could detect changelings and thats' when they infected him. The Founders separately made him sick later in the season to make him rejoin the link and be judged. That's when they made him a solid but also got infected by the Section 31 virus.

He met Laas midway through season 7 and wasn't cured until after, so Laas should be infected too.
>>211856999
poor Laas :(