Welcome to the Forum. It sounds as though this 'protectiveness' has been going on a long time. I agree that probably it would be best to get help from a behaviorist but make sure that they have experience of Basenjis. In the meantime keep him away from your guests. It's possible that he's stirred up by the excitement so it's best to try to keep him calm when people are around.
yep last time it looked like that…. Ziggee was angry... beyond words to describe, but after a minute, he focused again on me, and came back to his loving self, thank god.
Where in Ontario? I also live in Ontario and know of litters and puppies. Same thing as dmcarty. You can click on my name and then on my website, or go to the BCOC website @ http://www.basenjiclubofcanada.com/
Depending on where you live, I may know of someone close.