Kerby, P JQuiroga, J LMcGrane, J JStagg, D A2026-03-242026-03-2419970049-4747PMID:920330510.1007/BF02632320https://doi.org/10.1007/BF02632320https://andeanlibrary.org/handle/123456789/101427Vol. 29, No. 2, pp. 65-72Bovine brucellosis exists endemically at an estimated prevalence of 10% in the developing dairy industry of Santa Cruz in tropical Bolivia. This paper describes field testing of an FAO/IAEA indirect ELISA for brucellosis, as a possible replacement confirmatory test for the complement fixation test (CFT). The ELISA and CFT were compared on sera from 3 cattle populations: a non-vaccinated negative population, an S19-vaccinated negative population, and a brucellosis-positive population of unknown vaccination status. The CFT and ELISA showed excellent specificities of 100% and 98% respectively against the negative non-vaccinated group. The CFT maintained a specificity of 98% against the S19-vaccinated negative group, but ELISA specificity fell to 83% using a cut-off of 20% of positive control, and 94% using a cut-off of 40% of positive control. Against sera from the positive population, the ELISA gave many more positive reactions than the CFT, probably a combination of both higher sensitivity and lower specificity. It is concluded that as Santa Cruz is entering a phase of brucellosis control rather than eradication, the extra sensitivity of the ELISA is not valuable enough to risk a higher level of false positive reactions, especially as S19 vaccination is being increasingly used.engArtículo Científico Publicado