Evaluation of five serological tests for the diagnosis of porcine brucellosis in French Polynesia.

Porcine brucellosis due to Brucella suis biovar 1 raises important issues for pig breeders in French Polynesia. In this region, the disease is enzootic, spreads silently and engenders economic losses in infected farms as well as sporadic human cases. While serological tests are essential in surveillance and control programmes of animal diseases, to date none of the available tests have been shown to be reliable enough to be used as a gold standard in routine individual diagnosis of porcine brucellosis. Few studies about the estimation of the sensitivity and the specificity of porcine brucellosis screening tests have been published, none of them dealing with French Polynesia. The studied population included 1,595 pigs from French Polynesia. Five tests were evaluated: Rose Bengal test, fluorescence polarisation assay, indirect ELISA, and two competitive ELISAs (C-ELISA). The sensitivity and the specificity of each test were estimated. C-ELISA2 was the most sensitive test (Se C-ELISA2=0.954 [0.889; 0.992] 95% credibility interval (CrI)) while both C-ELISA and Rose Bengal test (RBT) were the most specific ones (Sp C-ELISA1=0.856 [0.806; 0.915] 95% CrI; Sp C-ELISA2=0.849 [0.817; 0.879] 95% CrI; Sp RBT=0.853 [0.812; 0.898] 95% CrI).