There is a lot of confusion, so I am going to clarify that this is not medical advice. The information is very relevant for people who want to buy parasite preventers, which are expensive and some of them even can make you sick.
The fact is, it is very unlikely that parasites cause any type of illness. I am not a medical doctor so I can't tell you that it is impossible to get sick from parasites. However, the evidence clearly shows that most people who are healthy have a parasitic infection in their bodies. If you have a parasite infection in your body, it's possible to have the following symptoms:
diarrhea, fever, pain, swollen joints and the like. Most parasites in the body are not harmful to the body, and there is no reason to avoid them. There are over 4,000 different species of parasite. They are found in many different environments in the world. This is where they are most likely to be found. The more different the species, the more likely that parasite is to be present. But the best way to find out about the source of the parasite is to treat it. A parasite that causes illness or problems for a person, is usually not a good thing.