The description I've been given of the bug that closed RIU's at Bahia Maimon is vague - Norovirus, a.k.a. Norwalk-like, a.k.a. stomach flu, a.k.a. gastroenteritis.
Health checks ruled out food and water / sanitation.
Just got back and I know a few people went down with sickness / diarrhoea. But this is a very few out of all the guests at the 3 hotels. One person was even ill on the very first day.
There is nearly always someone with this kind of problem at hotels in hot climates whether it is DR, Mexico, Egypt ...