Hi Scuba Lady, I'm not a beekeeper but I have friends who are. Not sure the history about how they became africanised, but they all are. I realise this is not a scientific source but I can't be bothered to do a more detailed search - though I'm sure you'll find more info if you look.
"Virtually all the honeybees you see in Belize are now Africanized and are present in most areas, even Ambergris Caye. If you stumble on a hive, try to get under a roof (bees usually won't follow you under a shelter) or into water." http://www.belizefirst.com/10watch.html