• Card Agglutination Test for Trypanosomiasis (CATT) End-Dilution Titer and Cerebrospinal Fluid Cell Count as Predictors of Human African Trypanosomiasis (Trypanosoma brucei gambiense) Among Serologically Suspected Individuals in Southern Sudan.

      Chappuis, F; Stivanello, E; Adams, K; Kidane, S; Pittet, A; Bovier, P A; Médecins Sans Frontières, Swiss Section, Geneva, Switzerland. francois.chappuis@hcuge.ch (Published by: American Society of Tropical Medicine and Hygiene, 2004-09)
      The diagnosis of human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense relies on an initial serologic screening with the card agglutination test for trypanosomiasis (CATT) for T. b. gambiense, followed by parasitologic confirmation in most endemic areas. Unfortunately, field parasitologic methods lack sensitivity and the management of serologically suspected individuals (i.e., individuals with a positive CATT result but negative parasitology) remains controversial. In Kajo-Keji County in southern Sudan, we prospectively collected sociodemographic and laboratory data of a cohort of 2,274 serologically suspected individuals. Thirty-three percent (n = 749) attended at least one follow-up visit and HAT was confirmed in 64 (9%) cases. Individuals with lower initial CATT-plasma (CATT-P) end-dilution titers had lowest risks (10.4 and 13.8/100 person-years for 1:4 and 1:8 titers, respectively) that significantly increased for higher dilutions: relative risks = 5.1 (95% confidence interval [CI] = 2.6-9.5) and 4.6 (95% CI = 2.8-9.8) for 1:16 and 1:32 titers, respectively. The cumulative yearly risk was also high (76%) in individuals found with 11-20 cells in the cerebrospinal fluid, but this involved only eight patients. Adjustment for potential confounders did not affect the results. In conclusion, treatment with pentamidine should be considered for all serologically suspected individuals with a CATT-P end-dilution titer >/= 1:16 in areas of a moderate to high prevalence of HAT.
    • Trypanosoma Brucei Gambiense Trypanosomiasis in Terego County, Northern Uganda, 1996: A Lot Quality Assurance Sampling Survey.

      Hutin, Y; Legros, D; Owini, V; Brown, V; Lee, E; Mbulamberi, D; Paquet, C; Epicentre Office in Uganda, Kampala, Uganda. (Published by: American Society of Tropical Medicine and Hygiene, 2004-04)
      We estimated the pre-intervention prevalence of Trypanosoma brucei gambiense (Tbg) trypanosomiasis using the lot quality assurance sampling (LQAS) methods in 14 parishes of Terego County in northern Uganda. A total of 826 participants were included in the survey sample in 1996. The prevalence of laboratory confirmed Tbg trypanosomiasis adjusted for parish population sizes was 2.2% (95% confidence interval =1.1-3.2). This estimate was consistent with the 1.1% period prevalence calculated on the basis of cases identified through passive and active screening in 1996-1999. Ranking of parishes in four categories according to LQAS analysis of the 1996 survey predicted the prevalences observed during the first round of active screening in the population in 1997-1998 (P < 0.0001, by chi-square test). Overall prevalence and ranking of parishes obtained with LQAS were validated by the results of the population screening, suggesting that these survey methods may be useful in the pre-intervention phase of sleeping sickness control programs.