Use of polymerase chain reaction in human African trypanosomiasis stage determination and follow-up

Stage determination of human African trypanosomiasis is based on the detect ion of parasites and measurements of biological changes in the cerebrospina l fluid (CSF) (concentration of white blood cells > 5 cells per mm(3) and i ncreased total protein levels). The patient is treated accordingly. Demonst ration of the absence or presence of trypanosomes by the double centrifugat ion technique is still the only lest available to clinicians for assessing treatment success. in this study, however, we evaluate the polymerase chain reaction (PCR) as a tool for assessing the disease stage of trypanosomiasi s and for determining whether treatment has been successful. Ail 15 study p atients considered to be in the advanced stage of the disease were PCR posi tive; however, trypanosomes were demonstrated by double centrifugation in o nly 11 patients. Of the five remaining patients, who were considered to be in the early stage, PCR and double centrifugation were negative. Following treatment, 13 of the 15 second-stage patients were found to be negative for the disease in at least two samples by PCR and double centrifugation. Two others were still positive by PCR immediately and one month after the treat ment. Trypanosome DNA detection using PCR suggested that the two positive p atients were not cured bur that their possible relapse could not be identif ied by a search for parasites using the double centrifugation technique. Fu rther evaluation of the PCR method is required, in particular to determine whether PCR assays could be used in stud ies on patients who fail to respon d to melarsoprol, as observed in several foci.