Yes Valley Fever is a disease that is very common around here, it is cause by spores that live in the dirt here in the desert, However since your dogs will only be here for a weekend they will be fine. Dogs usually get it because they live here for an extended period of time and dig in the dirt making their lungs exposed to it. Missy has never had Valley Fever before and we adopted her over 2 years ago. Just make sure while they are here they aren't digging in the dirt and they won't catch it.