Um yes. Pet stores don't give a diddly about the quality of animal they sell to you, 'specially rodents, they're "disposable" Quaritine your animals to ake sure they're not carrying anything. PROBABLY NOT. Althouh you can buy special worming stuff for your fully grown mouse, I think you can also buy stuff to keep away mites. Ask your local petshop if they sell worming stuff and how to use it.