You'll find some information on IPSID at www.basenjiclubvic.org/ipsid.html
It can be exacerbated by stress.
Was Nilo perfectly well when he had his vaccination? When you said this past WEdnesday did you mean the Wednesday this week?
Thank you for the link, I do not know if there is a particular age when basenjis start showing IPSID symptoms, all that I know so far is I can not relate his diarrhea episodes to any stressful situation. Besides he has not shown any hair loss or lack of apetite. This is the first time that I see him lacking of apetite. His coat is shiny, not dry at all, either.
The vaccines were administered this Wednesday, two days ago. On Wednesday morning he was fine, his stools were completely normal, but towards the afternoon, before taking him to the vet, I observed that they had turned soft, but the worst was last night, when he started vomiting. That had never happened before! Right now he is sleeping, he has not vomited again and he is not in a rush to go to the bathroom anymore.