A comparison of parasitological methods for the diagnosis of gambian trypanosomiasis in an area of low endemicity in Côte d'Ivoire.

The card agglutination test for trypanosomiasis (CATT) was used to examine 8974 inhabitants in 14 village areas south-west of Daloa, Côte d'Ivoire; 114 (1.3%) were CATTT or +/-, and were further examined by one or more of 6 methods for the direct detection of trypanosomes: lymphatic gland puncture, stained thick blood film (TBF), haematocrit centrifugation technique (HCT), mini-anion exchange column (MAEC), quantitative buffy coat method (QBC), and kit for in vitro isolation of trypanosomes (KIVI). Trypanosomes were seen by at least one method in 16 (14.0%) of the CATT+ group. Blood from 356 of the 8860 CATT- group was inoculated into KIVI; trypanosomes grew from the blood of 1 person. Eleven of the 17 patients with detectable trypanosomes were screened by all 6 methods: 6 were HCT+; 7 were gland+; 10 were MAEC+; 10 were KIVI+; 11 were both TBF+ and QBC+. One CATT+ patient was KIVI+ but otherwise negative, although TBF was not done. The overall prevalence of trypanosomes was 0.2% rising to 0.8% in one village area. The results support previous evidence that a reappraisal of procedures is required in the customary system of surveillance for gambian sleeping sickness.