Luke Turner 🦠

Enterobius vermicularis ova were identified on stool microscopy from a 9-year-old child. Microscopic appearance: The eggs are colorless, smooth and ovoid, with a moderately thick, double-layered shell. One side is characteristically flattened, giving the egg its classic “D-shaped” appearance. They measure approximately 50–60 × 20–30 µm. Unlike the eggs of many other intestinal nematodes, E. vermicularis eggs are passed partially embryonated, and a developing larva may sometimes be visible within the egg. About the parasite: E. vermicularis is a nematode (roundworm) with a worldwide distribution. Infection is particularly common in children. Adult worms inhabit the cecum and adjacent colon. At night, gravid female worms migrate to the perianal region to deposit their eggs. This explains the characteristic symptom of nocturnal pruritus ani (night-time anal itching). In heavier infections, sleep disturbance, irritability and reduced appetite may occur. Although E. vermicularis eggs may occasionally be detected in stool—as in this case—stool microscopy is not the optimal diagnostic method. The preferred method is the cellophane/cellulose adhesive tape test, performed on the perianal skin, ideally in the morning before bathing or defecation. A beautiful example of how a characteristic microscopic morphology can point directly toward the diagnosis. #Fortheloveofmicrobiology #clinicalmicrobiology #microrounds #IDpath #ASMClinmicro #STEM #womeninmicrobiology #microbiologypakistan #pathbugs