11. Trypanosoma cruzi – This parasite is most commonly found in the southern United States, and if you're lucky, you will not have to worry about it. If you aren't lucky, you might find yourself contracting the Chagas disease, which can cause heart failure 10 to 20 years down the road.
10. Taenia solium – For more than a few people, getting seizures is a fairly scary prospect, so for them getting a series of seizures from a parasitic life form is even scarier. Thankfully, so long as you make sure that you do not ingest raw meat, you should be fine to avoid this tricky customer.
9. Naegleria fowleri – Let's start it off with a bang – this thing is called the “brain-eating amoeba.” Just swimming around in the wrong body of water can cause you to suffer its symptoms, which can include a rare brain infection. Thankfully, you cannot become infected by it by simply swallowing contaminated water.