Tropical parasites

I have vacationed in many Southern locales out of the US such as: Cayman Islands, Bahamas, Costa Rica and Mexico. I became extremely ill in San Jose, CR on day 2 of trip with violent double ended purging, and I still felt bad 2-3 weeks back in the states. Is there any parasite that is indigenous to downtown San Jose, CR and produces those kinds of symptoms. I've had symptoms of parasites for a long time, but only realized it for what it was a year and a half ago. My immune system is crap from mono, severe allergic reactions(sumac), and viral infections; but hopefully improving. Any info or ideas would be greatly appreciated. Tweet