Authors
I M Vincent3; S Bisser1; R Daly3; S Biéler1; B Courtioux2; J M Ndung�u1; M P Barrett3; A Cattanach3; 1 FIND, Switzerland; 2 Université de Limoges, France; 3 University of Glasgow Discussion
HAT is stratified based on the species of trypanosome causing the disease and the stage of the disease. Treatment depends upon the causative parasite and the disease stage. Currently staging depends upon detecting parasites or elevated white blood cell numbers in CSF. Improved staging is desirable, as is the elimination of the need for lumbar puncture. Here we probe samples of CSF, serum and urine from Angolan patients infected with T. b. gambiense, at different disease stages. Urine samples provided no robust markers indicative of infection stage (due to inherent variability in urine concentrations). CSF was very clearly able to distinguish patients at S1 or S2. Eleven metabolites clearly distinguished stage in most patients and two of these (neopterin and 5-hydroxytryptophan) showed 100% specificity and sensitivity between S1 and S2. 5-hydroxytryptophan, oleamide and linoleamide, metabolites involved in somnolence, showed altered levels thus offering a metabolic mechanism underpinning the eponymous symptoms of “sleeping sickness”. Serum was also able to yield several biomarkers clearly indicative of the stage of infection. A logistic regression model including these metabolites showed clear separation of patients being either at S1 or S2 with good sensitivity (92%) and specificity (81%). Development of these markers into a rapid diagnostic test could help in the elimination of HAT. 
