Development of an indirect ELISA based on a recombinant chimeric protein for the detection of antibodies against bovine Babesiosis

JARAMILLO ORTIZ J; MONTENEGRO, VALERIA NOELY; DE LA FOURNIERE S; SARMIENTO N; FARBER M; WILKOWSKY S. E

Cairns

Congreso; 9th Tick and Tick Borne Pathogen Conference & 1st Asia Pacific Rickettsia Conference; 2017

An indirect enzyme-linked immunosorbent assay (iELISA) based on a recombinant multi - antigen of Babesia bovis was developed for detection of antibodies in bovines suspected of infection with this parasite. The multi-antigen comprises gene fragments of three previously characterized B. bovisantigens: MSA-2c, RAP-1 and the Heat Shock protein 20 that are well conserved among geographically distant strains. The iELISA was used to initially evaluate 75 known - positive and 268 known - negative bovine sera previously tested for antibodies to B. bovis by the gold-standard ELISA based on a crude merozoite lysate. A cut off value of > 35% was determined in these samples by receiver operator characteristic (ROC) curve analysis, showing a sensitivity of 95.9% and a specificity of 86.2%. The iELISA was further tested in a blind trial using an additional set of 263 field bovine sera from enzootic or tick-free regions of Argentina. Results showed to be in good agreement with the gold standard test with a Cohen´s kappa value of 0.76. The seroprevalence of bovine babesiosis in tick enzootic regions of Argentina was analyzed with the new iELISA and values among 68 - 80% were obtained. The chimerical multi-antigen showed cross - reaction with samples from B. bigemina infected cattle which can be attributed to some conservation between 2 of the 3 antigens. This new iELISA based on a recombinant antigen would be a simple, low-cost technique and appears to be well suited to perform epidemiological surveys in regions where ticks are present and no previous infection rates are recorded