Signs and symptoms of parasitic infection vary from one individual to another. The more common signs and symptoms are: constipation, diarrhea, bloating, gas, symptoms of irritable bowel syndrome, arthralgias, myalgias, anemia, increased allergic reactions, skin lesions, agitation and anxiety, difficulty sleeping, decreased energy, malnutrition and decreased immune function. Infection can occur by four different pathways. These routes include: Contaminated food or water Insect vectors Sexual contact Passage through the skin and nose Most people are inclined to believe that parasitic infection is a rare and exotic occurrence, limited to those who have traveled to distant, tropical lands. However, there has been an increase in the incidence of parasitic infection in this country. These may include: Contamination of the water supply Increased use of daycare centers Increased travel to, and visits from, countries where parasitic infection is endemic Household pets Consumption of exotic and uncooked foods Antibiotic use Changing sexual partners