The Importance of Definitive Diagnosis in Chronic Schistosomiasis, with Reference to Schistosoma haematobium

Abstract

Schistosomes are long-lived parasites, hence schistosomiasis is a chronic disease with severe long-term implications. However, definitive diagnosis of active infection has been difficult because demonstration of infection has depended on detecting parasite eggs in urine and/or stool. In the case of Schistosoma haematobium which parasitizes the urinogenital system, this method has low sensitivity in adults. Detection of parasite-specific DNA in urine has been demonstrated and this has similar specificity but improved sensitivity. The implications of this new procedure and the impact on diagnosis are discussed.

Figure 1

The proportion of Schistosoma haematobium cases diagnosed by demonstration of eggs or schistosome-specific DNA in the urine. 398 specimens were collected from villagers in western Nigeria where the parasite is endemic. Numbers in table = number examined,  P  values given where significant.