Available data regarding the distribution, prevalence and severity of various diseases are based on the performance and operational characteristics of the diagnostic techniques applied; this is a fact that is particularly apparent in the study of helminth infections. An important lesson learnt from the efforts to rein in dracunculiasis, lymphatic filariasis and schistosomiasis is that the diagnostic approach needs to be changed as further progress is made towards control and ultimate elimination of the disease. This insight prompted the opinion piece presented here, which highlights diagnostic dilemmas in helminthology related to the stage of control achieved and sets out some research needs.
