Vet - instantly, and probably starve her for 24 - 36 hours afterwards. Then boil rice, coddle an egg, cook chicken or fish and use the water to moisten the rice. Small meals, more often and gradually reintroduce her normal diet. And Yoghurt will replace the flor in her stomach. The good bacteria - Basenjis love it. You should also have concentrate electrolytes in the house at all time so you can prevent the little folks from becoming dehydrated. But Vet first. Good luck.
You mention electrolytes... like Pediolyte (for kids)? Is that safe for dogs?
No idea. I get it from the Vet in sachets, especially for animals. Normally it comes in two different packets and you mix them with water so they combine. I also have veterinary electrolyte concentrate in a bottle. Also from a veterinarian. If push comes to shove and you need to get a Basenji to drink to prevent dehydration, a little honey in the drinking water can be very helpful