my son and I both have strep throat

I dont think it will affect your guinea pigs and I HIGHLY doubt it will affect your cat although I don't know much about them. Get better!

Just be extra careful while you're sick. Wash your hands before and after preparing their food or water bottles. I'd really avoid handling until you're feeling better, only doing the necessary cleaning/feeding/etc.

Whether or not it's contagious I don't know. Guinea pigs can get bacterial infections from us, but not viral.

According to Wikipedia ( which isn't all that great,) there are both viral and bacterial forms of it. I don't know if any of them can infect guinea pigs, however. I know they cannot get colds from us, but I don't know about strep throat.

Thank-you every one for your help. We will be extra diligent until the 48 hours on antibiotics kicks in (when the Dr said we are no longer contagious)

True strep throat is a bacterial infection, from the bacterium streptococcus.

Since cavies can get bacteria from use, I would us extra caution.

Colds are typically viral.