Some common intestinal worms that affect people include hookworms, roundworms and whipworms, notes World Health Organization. These worms are common in areas with poor sanitation and are transmitted by eggs found in human feces.
Symptoms caused by intestinal worms include diarrhea, abdominal pain, weakness and general malaise, explains World Health Organization. Patients with hookworms can also experience severe intestinal blood loss that leads to anemia. Conditions that increase the risk of getting intestinal worms include international travel, living in areas prone to intestinal parasites, poor personal hygiene, poor sanitation and a weak immune system, according to University of Maryland Medical Center.