Development of EMA-2 recombinant antigen based enzyme-linked immunosorbent assay for seroprevalence studies of Theileria equi infection in Indian equine population

Equine piroplasmosis is a tick-transmitted protozoan disease caused by Theileria equi and/or Babesia caballi. In the present study, we expressed a 53 kDa protein from the truncated EMA2 gene of T. equi (Indian strain) and developed EMA-2ELIS A using this expressed protein. This ELISA is able to detect T. equi-specific antibodies in experimentally infected animals as early as 9 days post-infection. The assay developed was validated with the OIE recommended competitive ELISA (cELISA) on 120 serum samples and significant agreement (kappa = 0.93) was observed between results of both the ELISAs which indicates suitability of (EMA-2)ELISA for use in sero-diagnosis. Diagnostic sensitivity and specificity of (EMA-2)ELISA - as compared with cELISA - were 0.97 and 0.96, respectively. Analysis of 5651 equine serum samples - collected during 2007-2012 from 12 states of India representing eight agro-climatic zones - by (EMA-2)ELISA revealed 32.65% seroprevalence of T. equi in India. In conclusion, the (EMA-2)ELISA developed using the T. equi EMA-2 recombinant protein as antigen for detecting T. equi-specific antibodies has good diagnostic potential for sero-epidemiological surveys. (C) 2013 Elsevier B.V. All rights reserved.