Comparative evaluation of parasitological, serological and DNA amplification methods for diagnosis of natural trypanosomal infection in equines.

The study was conducted to evaluate and compare the parasitological (micro-haematocrit method, MHCT), serological (enzyme-linked immunosorbent assay, ELISA) and molecular (polymerase chain reaction, PCR) methods for diagnosis of trypanosomal infection in equines. Blood samples, taken from 500 animals (horses and donkeys), were primarily screened with formol gel test. Of 500 samples examined, 120 samples were found positive with formol gel test. Later, these samples were further processed for the parasitaemia with MHCT, detection of antibody against trypanosmal antigens positive ELISA and trypanosomal DNA using PCR. Results showed that higher number of positive samples (p < 0.05) were detected with PCR (30.8%) compared to either ELISA (21.6%) or MHCT (17.5%). The sensitivity and specificity of ELISA were 85.7% and 79.5%, respectively compared to PCR which were found to be 100% and 58.97%, respectively. To conclude PCR test was found to be a superior test over MHCT and ELISA for the diagnosis of trypanosome in equines and can be used in field conditions.