Prevalence of equine infectious anemia virus in horses and donkeys determined by comparison of ELISA and AGID in Mexico

Abstract

From February to December 2021, 960 serum samples from different climate regions in two Mexican states were analyzed for antibodies against EIAV using competitive enzyme-linked immunosorbent assay (cELISA) and agar gel immunodiffusion (AGID) tests. The overall seroprevalence of EIAV infection in equids determined by ELISA and AGID tests was 19.69% and 17.60%, respectively. The highest rate of seropositivity was observed in the state of Veracruz (23.67%, using AGID test), and the lowest rate was found in the state of Puebla (13.12%, using cELISA test). In total, 17.45% (85/487, using AGID test) and 15.40% (75/487, using cELISA test) of horses were positive for EIAV infection. Donkeys showed a prevalence of 19.87% (94/473) in cELISA and 21.99% (104/476) in AGID. The cELISA was compared with AGID as the gold standard test. The diagnostic sensitivity for horses and donkeys was 90.4% and 92.2%, and the specificity was 97.5% and 97.3%, respectively, with an almost perfect degree of agreement (kappa values of 0.871 and 0.888). Therefore, the overall seroprevalence rate of EIAV infection in equines in the sampled states of Puebla and Veracruz was 19.3%, with 91.4% sensitivity, 97.4% specificity, and an agreement of 96.25%, indicating almost perfect agreement (kappa = 0.880).