Validation of a Commercial Glanders ELISA as an Alternative to the CFT in International Trade of Equidae

Abstract

Glanders, caused by Burkholderia (B.) mallei is a notifiable zoonotic disease in equidae. For international trade and movement of equids, certificates of negative serological test results for antibodies against B. mallei are required. To date, the complement fixation test (CFT) is the mandatory test to issue these health certificates. The CFT is difficult to standardize and, due to its poor specificity, often leads to false-positive reactions resulting in trade restrictions with considerable financial consequences. In the present study, the new ID Screen Glanders Double Antigen Multispecies ELISA (GLANDA- ELISA) (IDvet, Grabels, France) was evaluated using 400 negative and 370 glanders positive field samples of equidae. The GLANDA-ELISA was significantly more specific (99.8%) than the CFT (97.0%). Considering the comparable sensitivities of CFT (96.5%) and ELISA (98.1%), this new GLANDA-ELISA test appears a suitable confirmatory test and a realistic alternative for serological testing of horses for trade or movement.

Protein Microarray-Guided Development of a Highly Sensitive and Specific Dipstick Assay for Glanders Serodiagnostics

“…2 and 3 and confirmed by statistical analysis (Table S4), 12 out of 22 protein antigens (BPSS1498, BPLS2697, BPSS0477, BPSS1840, BPSL2522, BPSL2096, BPSS2141, BPSL1445, BPSL2698, BPSS0476, BPSL2520, BPSS1532) differed significantly between sera from panel P1 and control sera from panels P2 and P3. The highest signal intensities on average were obtained for BPSS1498 (Hcp1), BPSL2697 (molecular chaperone GroEL1), and BPSS0477 (molecular chaperone GroEL2), proteins of interest that have already been mentioned for glanders ( 17 , 19 , 20 ), but also for new proteins described in our study, such as BPSS1840 (putative N -acetylmuramoyl- l -alanine amidase), BPSL2522 (outer membrane protein A precursor), and BPSL2096 (putative hydroperoxide reductase).…”

“…The following three panels of equid sera were included in this study: P1, 30 positive sera from clinically confirmed glanders cases from Pakistan, where the disease is endemic; P2, 14 control sera of horses infected with pathogens other than B. mallei (dourine [ n = 3], equine metritis [ n = 5], equine infectious anemia [ n = 2], and viral arthritis [ n = 4]), provided by the European Reference Laboratory for Equine Diseases; and P3, 39 sera of healthy controls obtained from officially glanders-free countries (France [ n = 7], Ireland [ n = 3], and Tunisia [ n = 29]). In agreement with previous studies, horses showing clinical signs related to glanders were regarded glanders cases if they were positive in a serological assay (CFT, indirect ELISA [iELISA]) or in close contact with glanders-positive horses during culture-confirmed outbreaks ( 19 , 20 ). No ethical approval was required for this study because field sera from the P1, P2 and P3 panels were collected for monitoring and diagnostic purposes.…”

“…Alternative tests (Western blot, enzyme-linked immunosorbent assays [ELISAs], Luminex) have been developed, and recent validation works give hope for improving the glanders diagnostic performance ( 16 – 18 ). In particular, the use of recombinant proteins (including Hcp1 and GroEL) has recently led to promising prospects for glanders diagnosis ( 17 , 19 , 20 ). However, additional antigens might be useful to increase the performance of serodiagnostic glanders tests and distinguish between exposure and disease, acute and chronic forms, or melioidosis and glanders.…”

Assessment of the control measures of the category A diseases of Animal Health Law: Burkholderia mallei (Glanders)

“…Alternative serological tests based on B. mallei protein extracts or recombinant proteins have been developed and recent comparison studies concluded that sensitivity and specificity of evaluated tests were comparable with those obtained with the complement fixation test, opening the possibility of replacing it by more easily standardisable methods (Elschner et al, 2017(Elschner et al, , 2021. Nevertheless, one of the current constraints for ELISAs is their availability in a commercial format.…”

First glanders cases detected in Nepal underscore the need for surveillance and border controls

“…Sera from these five equids were analyzed with five different serological tests: (i) CFT [ 6 ], (ii) ID Screen® Glanders indirect ELISA (IdVet, France) [ 7 ], (iii) GLANDA ELISA (IdVet, France) based on two recombinant proteins [ 8 ], (iv) Luminex® bead-based assay targeting Hcp1 and GroEL proteins [ 9 ], and (v) ELISA based on a glycoengineered protein of Burkholderia recently validated for glanders diagnosis (Glyco ELISA) [ 10 ]. Two horses (L/157, B/120) and one mule (B/113) were positive by all tests and positive or undetermined results were obtained for all animals with ID Screen® Glanders indirect ELISA , GLANDA ELISA and Luminex® tests.…”