I think Jim is right that this may well be a colonial
daga. I don't think it is Filipino because the hilt is very unusual for
Ilokano work and they produced most of these style daggers coming from the Philippines.
South America seems likely. There is a similar style knife in the essay on
Gaucho Knives by Abel Domenech on this site. Brazil, Argentina, Chile are all possibilities. Perhaps you could send an email with a picture to Mr. Domenech and ask him for his thoughts. He has replied to previous requests from Forum members and seems a generous person with his knowledge.
Ian