Figure 2. PCA factor score plots of MS peak intensity values for the 14 candidate onchocerciasis biomarkers.

Mass feature intensity values were extracted through ESI-TOF+/XCMS analysis of (A) African blood serum and plasma samples from 55 O. volvulus infected individuals compared against 18 healthy controls. (B) A sample set including 76 O. volvulus infected individuals compared against 56 O. volvulus negative controls (including healthy and those infected with other tropical diseases). (C) An extraction of only those data points representing the 21 Guatemala O. volvulus infected individuals compared against 18 healthy controls. Individual data points are symbolized using the following code for country of origin and disease status: “blue diamond” = Cameroon Ov−, “blue circle” = Guatemala Ov−, “blue astrisk” = Scripps Ov−, “green circle” = Leishmaniasis Ov−, “green square” = Chagas Ov−, “green triangle” = LF Ov−, “pink diamond” = Cameroon Ov+, “pink circle” = Guatemala Ov+, “pink square” = Ghana Ov+ (1986, 1991 and 2003 samples), “pink triangle” = Liberia Ov+, “orange diamond” = Cameroon Ov?.