Kerby PJ, Quiroga JL, McGrane JJ, Stagg DA. Field evaluation of an indirect ELISA for detection of brucellosis in lowland Bolivia.
Trop Anim Health Prod 1997;
29:65-72. [PMID:
9203305 DOI:
10.1007/bf02632320]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Bovine 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.
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