Dientamoeba fragilis is a species of unicellular protozoa found in the digestive tract of some humans, pigs and gorillas. In some people, the infection causes gastrointestinal disturbances. Usually they are mild and include variable intensity: diarrhea, abdominal pain and lack of appetite. The infection is asymptomatic in 75-85% of children, but in children the symptoms are present in up to 90% of infections. Symptoms of acute infection last for 1-2 weeks. A symptom of chronic infection is abdominal pain that may last several months.
The genus Blastocystis consists of several species (subtypes) that infect the digestive tract of humans, farm animals, birds, rodents, reptiles, amphibians, fish, and cockroaches. The Blastocystis protozoa have low host specificity. On the basis of genetic differences, the genus Blastocystis has been divided into 9 subtypes. Each of the subtypes has been found in the digestive tract of humans. The most common subtype in humans is subtype 3. Blastocystis is one of the most common human parasites. It is estimated that 5% of the human population is infected with this protozoon, and the percentage of infected indivituals in some areas reaches 100%. A particularly high incidence is observed in people working with animals. The protozoan Blastocystis causes blastocytosis. chronic diarrhea or loose stools, abdominal pain, irritable bowel syndrome, weakness, fatigue, weight loss. Most infections are asymptomatic. Very severe symptoms can occur in people with acquired or congenital impairment of the immune system.

Diagnostic test AmpliTest Digestive System Parasites IV (Real Time PCR) allows detection in a single reaction the DNA sequences specific to protozoans Dientamoeba fragilis and Blastocystis sp. subtype 3 in DNA preparations obtained from feces samples. The Real Time PCR is a triplex-type. The Cy5 channel serves for detection of the DNA sequences specific for Blastocystis sp. subtype 3 whereas Dientamoeba fragilis-specific DNA sequences are detected in the Texas Red channel. The HEX channel is reserved for monitoring of the internal control amplification. Additionally, diagnostic panel contains negative and positive controls allowing to monitor the whole aspects of the Real Time PCR. Positive control was obtained using genetic engeeniring.