Authors:S. Omanwar, J. R. Rao, G. Butchaiah, S. H. Basagoudanavar and R. K. Singh
The mechanically transmitted haemoflagellate,Trypanosoma evansicauses 'surra', a wasting disease of domestic animals and is highly endemic in distribution in Southeast Asia. The detection ofT. evansiis important for improving the epizootiological and animal health status of the region. The specificity and sensitivity of polymerase chain reaction (PCR) using oligonucleotide primers constructed fromT. evansirepetitive DNA sequences were studied in the present investigation. Using the assay, it was possible to amplify template DNA ofT. evansiderived from buffaloes, camels and horses to a threshold sensitivity level of 0.5 pg and to detect DNA from as few as five organisms in 10 (l crude blood samples. Following experimental infection of calves with 5 × 105T. evansi, positive signals could be observed as early as 12 h post-infection. DNAs from two common haemoflagellates of cattle,Babesia bigeminaandTheileria annulatawere not amplified with the primers.
Authors:S. H. Basagoudanavar, J. R. Rao, Swati Omanwar, A. K. Tiwari, R. K. Singh, R. S. Kataria and G. Butchaiah
A highly reproducible, dominant, monomorphic fragment of 473 base pair (bp) amplified from the genome of Trypanosoma evansi by arbitrary primer — polymerase chain reaction (AP-PCR) was labelled with digoxigenin and investigated for its potential as DNA probe. Dot-blot hybridisation of total genomic DNA with the probe proved useful in detecting bubaline, cameline and equine strains of T. evansi down to 10 pg of parasite template DNA. No cross-hybridisation was seen with Babesia bigemina, Theileria annulata and the bubaline host DNA. This probe may facilitate laboratory identification of T. evansi in developing countries, without the inherent risk associated with radioisotopes.