Parasites in urinary sediments include Trichomonas vaginalis, Enterobius vermicularis, and Schistosoma haematobium. Parasites and parasitic ova are usually present in urine sediment due to vaginal or fecal contamination.
The arrows in the top image on the right point to Trichomonas vaginalis. Trichomonas is usually a contaminant from vaginal infection and is often accompanied by an increased number of WBCs. Trichomonas is highly motile due to an undulating membrane and multiple anterior flagella; however, movement may deteriorate after 30 minutes. Confirmation of motility is essential for the identification of Trichomonas vaginalis. Non-motile organisms can resemble WBCs, transitional epithelial, or renal epithelial cells. For this reason, it is essential to examine a freshly collected urine sample.
Enterobius vermicularis (pinworm) is not a primary urine parasite. E. vermicularis ova (eggs) are usually a fecal contaminant in the urine sediment. The ova are oval in shape and smooth, with one side flattened. Embryos (larvae) may be visible within the ova. The bottom image on the right is an example of an E. vermicularis egg (400× magnification) with an embryo (larva) visible within the thick hyaline shell.
Schistosoma haematobium ova may rarely be seen in urine sediment. This parasite is considered an essential factor in the etiology of bladder carcinoma. The ova are elongated and are 60 × 160 microns. They are slightly transparent and possess a delicate terminal spine. An example of S. haematobium ovum is shown below.
Schistosoma haematobium.
