Only rarely is there any visible evidence of infection. Moreover, many laboratories fail to detect the presence of parasites even when presented with specimens from infected persons. It is therefore sometimes necessary for the patient to determine whether infection is likely and to self-administer some remedy since allopathic medicine requires a diagnosis before prescriptions can be written. Once a condition has moved from acute to chronic, there may be alternating periods of constipation and diarrhea, abdominal distention and bloating, intestinal cramping followed by burning sensations and the sudden urge to eliminate. Generally, there is malabsorption of nutrients, especially fatty foods.
Many parasites affect the nervous system and give rise to sleep disorders, such as insomnia.
In children, hyperactivity is common, but adults may have symptoms ranging from depression to anxiety. Some parasites affect the brain and memory. It is extremely easy to contract a parasite infection. Contaminated water is one source of infection. Improperly washed or undercooked food is a common means of infection.