The occurrence of Trypanosoma evansi in buffaloes in Indonesia, estimated using various diagnostic tests

The prevalence and incidence of Trypanosoma evansi infections in village bu ffaloes in Central Java were estimated using parasitological tests, two ant igen-detection ELISAs (2G6 Ag-ELISA and Tr7 Ag-ELISA), an antibody-detectio n ELISA (IgG ELISA) and a card agglutination test (CATT). Of 2387 village b uffaloes tested in five districts, 4% (95 % confidence interval [CI]: 3 %, 5 %) were positive with the microhaematocrit test (MHCT), 58 % (95 % CI: 56 %, 60 %) were positive with the 2G6 Ag-ELISA and 70 % (95 % CI: 68 %, 72 % ) were positive with the Tr7 Ag-ELISA. An increasing prevalence with age wa s found and the proportion of positive buffaloes was highest in the over 84 months-old age-group (68 %) with the 2G6 Ag-ELISA and in the 37-60 months- old age-group (78 %) with the Tr7 Ag-ELISA. Parasitaemic buffaloes were fou nd in more than half of the villages visited. Corrected village-specific pr evalence values obtained with the two Ag-ELISAs ranged from 0 % to over 100 %, and prevalence differed significantly (P less than or equal to 0.0001) between villages in four of the five districts. Overall, 10% of buffaloes t ested in markets were found to be parasitaemic and 39, 56 and 47 % were fou nd positive with the 2G6 Ag-ELISA, IgG ELISA and CATT, respectively. Incide nce rates varied according to the test used and ranged from 0.22 (95 % CI: 0.09, 0.44) to 0.44 (95 % CI: 0.24, 0.76), per animal-year at risk, in two villages. The results highlight the importance of using validated diagnosti c tests to obtain accurate estimates of prevalence and incidence. These par ameters are needed, for example in mathematical models, for the development and evaluation of different control strategies for T. evansi infections in buffaloes.