Find out how the giardia parasite (Giardiasis) might cause you permanent damage! Giardia diarrhea is caused by a parasite called giardia intestinalis, or giardia lamblia. Recent studies show that people who get a giardia infection can later develop chronic bowel symptoms, such as diarrhea, constipation, cramps, etc.  Sound familiar? I wrote on another page about how certain …