I have an amoeba infection, it can infect the heart, brain, lungs, liver, cause a serious liver abscess. It starts in the GI tract and causes nausea/vomiting I think. The treatment can be 10-14 days of flagyl/mitronidazole but there are other drugs. I think I got this from that terrible place Indonesia from eating infected street meat.
It was impossible to diagnose and took 4 stool tests over 2 years. I just hope that I really don't have asthma and it was caused by this amoeba and I don't have permanent organ damage.