Comparison of serological tools for reliable diagnosis of brucellosis circulation in the West-African context.

BACKGROUND: Brucellosis is listed as a priority disease in low-income countries like Guinea, facing challenges in logistics, equipment, competence, and cost limitations for diagnosis. Serological diagnosis is mainly performed by the Rose Bengal agglutination test (RBT) in the veterinary sector. We have compared its discriminative capacity with more sophisticated and expensive serological tests, such as multi-species or species-specific ELISA kits and Complement Fixation test (CFT).

METHODOLOGY/PRINCIPAL FINDINGS: A panel of 554 serum samples of pigs, goats, sheep, and cattle collected throughout Guinea from 2017 to 2019 where tested by RTB and ELISA tests in parallel at the Institut Pasteur de Guinée (Conakry) and the Brucellosis WOAH/EU Reference Laboratory of the French Agency for Food, Environmental and Occupational Health & Safety (Maisons-Alfort, France). ELISAs performed equally across laboratories (Kappa =0.867-0.958); RBT and ELISA showed 94-95% concordance. The CFT value of positive cattle samples also logically followed the RBT scores CONCLUSIONS/SIGNIFICANCE: In low-income countries like Guinea, the less expensive RBT can be regarded as a convenient routine Brucella diagnosis tool, assuming a solid experience of the operator following standard operating protocols and regular proficiency tests. As WOAH recommends confirmatory methods, the multispecies ELISA kit appears as a good candidate for conveniently trained and equipped laboratories.