Top of my vet's short list for those symptoms was parasites. The other choices (IBD or EPI) are not terribly common in Basenjis. Considering where you are, I think giardia is a good possibility, or perhaps some other parasite common to your area that a North American vet would not be familiar with. Metronidazole (Flagyl), if available, is probably the drug of choice (12/15 mg/lb orally every 12 hours for 5 to 7 days). Fenbendazole (Panacur, Safe-Guard) is often used with the antibiotic in stubborn cases. Or Fenbendazole alone, if that's all you can get hold of (22 mg/lb orally for 3 to 5 consecutive days is the dosage suggested). I'm not a vet, so it would be better if you could get definitive advice from one, but I know what it's like to search for information and not be able to obtain it! Good luck with her.
I just picked this up off a Border Collie forum, and I have no idea if it is accurate, but for what it's worth,:
"Did some more research on coconut and turns out it's pretty amazing stuff. THe lauric acid in the coconut has all kinds of benefits. It's an antimocrobial, anti bacterial, anti viral and antifungal…the list goes on, Lauric acid is suppoesd to kill giardia, so I thought I'd check out, I tossed a handful of shaved c in with her kibble...next morning she was back to normal. I've started putting a little coconut in all the dogs feed now, as we go down to the pond quite a bit...they also claim it will kill tape worms...I'd really be curious to check that out too."
So perhaps if you have access to coconut, it would be worth a try?
Our studies have confirmed that the MCSFA, dodecanoic acid (C: 12) (common name: lauric acid), is anti-giardial, with an LD50 concentration comparable to that of metronidazole, the drug of choice in the treatment of giardiasis.
http://cat.inist.fr/?aModele=afficheN&cpsidt=17146659