Summary: | We investigated urinary N-acetyltyramine-O,β-glucuronide (NATOG) levels as a biomarker for active <i>Onchocerca volvulus</i> infection in an onchocerciasis-endemic area in the Democratic Republic of Congo with a high epilepsy prevalence. Urinary NATOG was measured in non-epileptic men with and without <i>O. volvulus</i> infection, and in <i>O. volvulus-</i>infected<i> </i>persons with epilepsy (PWE). Urinary NATOG concentration was positively associated with microfilarial density (<i>p </i>< 0.001). The median urinary NATOG concentration was higher in PWE (3.67 µM) compared to men without epilepsy (1.74 µM), <i>p </i>= 0.017; and was higher in persons with severe (7.62 µM) compared to mild epilepsy (2.16 µM); <i>p </i>= 0.008. Non-epileptic participants with and without <i>O. volvulus </i>infection had similar NATOG levels (2.23 µM and 0.71 µM, <i>p</i> = 0.426). In a receiver operating characteristic curve analysis to investigate the diagnostic value of urinary NATOG, the area under the curve was 0.721 (95% CI: 0.633−0.797). Using the previously proposed cut-off value of 13 µM to distinguish between an active <i>O. volvulus </i>infection and an uninfected state, the sensitivity was 15.9% and the specificity 95.9%. In conclusion, an <i>O. volvulus</i> infection is associated with an increased urinary NATOG concentration, which correlates with the individual parasitic load. However, the NATOG concentration has a low discriminating power to differentiate between infected and uninfected individuals.
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