True prevalence of pinworm (Enterobius vermicularis) infection among children in Qwa-Qwa, South Africa

The pinworm or seatworm, Enterobius vermicularis is a cosmopolitan intestinal parasite of people, especially children. However, surveys of gastro-intestinal parasites carried out in South Africa have, except for one, consistently shown very low E. vermicularis prevalences of below 5%. This is because the worm's eggs are sticky and adhere to the peri-anal skin or clothing, so that few become incorporated in faecal matter and are therefore seldom recorded in faecal analyses. We describe a study carried out in the mountainous Qwa-Qwa area of the Free State to measure the true infection rate of this nematode using the 'Scotch-tape method' and to compare it with the 0.4% prevalence reported from the same area using faecal analysis among 969 school-going children. A prevalence of 45.3% amongst 148 paediatric (hospital-based) children was recorded using adhesive tape, which suggests that E. vermicularis is not only the most abundant helminth in this high-altitude region but is also the second most abundant of all the intestinal parasites infecting children there.