Molecular biology (and particularly PCR) has been increasingly used for the diagnosis of parasitic protozoa of medical interest. Technical improvements in the past decade include: simplification of DNA extraction, development of automated procedures and of real-time PCR permitting precise
quantification of parasitic load. In clinical practice, PCR is routinely used for the diagnosis of toxoplasmosis in the amniotic fluid of pregnant women and in immuno-compromised patients. It can be useful for the diagnosis of cutaneous and visceral leishmaniasis and to differentiate the pathogenic
amoeba Entamoeba histolytica from the morphologically identical but non-pathogenic Entamoeba dispar. Its use for malaria remains limited due to high cost. Molecular biology methods facilitate the study of parasitic populations and could be useful to identify possible relationships
between a particular genotype and virulence.