Ninety-eight serum and 108 urine samples were collected in Burundi, 130 serum and urine samples in Senegal. Before testing in ELISA, serum and urine samples were pretreated to remove interfering components. Samples from Burundi were diluted in alkaline buffer and heated to 70 °C (alkaline/heating), and samples from Senegal were treated with 4% trichloroacetic acid (TCA). Although both pretreatment methods are reported to work equally well ( Krijger et al. 1994 ), we chose to use the same pretreatment procedures as used in the studies in nearby endemic areas ( Polman et al. 1995 , 1998). However, for urine CCA detection, we cross-checked by submitting each series of samples also to the alternative pretreatment method.