Evaluation of enzyme-linked immunosorbent assays with recombinant antigens for the serodiagnosis of equine Babesia infections.

The research is about the evaluation of two enzyme-linked immunosorbent assays (ELISAs) with recombinant protein antigens, compared with the indirect fluorescent antibody tests (IFAT), for detecting specific antibodies to two species of Babesia in horse blood samples.

Introduction

• The research focuses on two species of Babesia, namely Babesia caballi and Babesia equi. These are tick-borne parasites that infect red blood cells and cause the often fatal disease called equine piroplasmosis.
• The point of interest in this study is serodiagnosis, which is the diagnosis of disease through the detection of antibodies or antigens in serum.
• Two kinds of tests were evaluated: enzyme-linked immunosorbent assays (ELISA), which use an enzyme to detect the presence of disease, and indirect fluorescent antibody tests (IFAT), which use a fluorescent dye to detect antibodies.

Methods

• The ELISAs used in this study are unique because they used recombinant protein antigens. Recombinant proteins are genetically engineered proteins expressing certain traits of interest.
• The study used 380 sera samples from different horses: some were experimentally infected, some uninfected, and others were ‘field horses’, or horses from the population at large.

Results

• The study found a high concordance of 92.4% and 98.2% between ELISA and IFAT for detection of B. caballi and B. equi, respectively. This means that absence/presence of disease as detected by ELISA agreed with IFAT results in the majority of instances.
• These concordances suggest that ELISA may be a viable alternative to IFAT for serodiagnoses of equine piroplasmosis. This is important because ELISA is generally cheaper, less time-consuming, and does not require highly skilled technicians compared to IFAT.

Conclusion

• Given these results, the study suggests that although there are improvements needed in the ELISA for B. caballi, ELISA is a good alternative testing method, especially for B. equi infection.