COMPARATIVE STUDY OF DNA EXTRACTION TECHNIQUES AND ITS USE IN THE POLYMERASE CHAIN REACTION (PCR) FOR THE DIAGNOSIS OF Theileria equi AND Babesia caballi.

Abstract

Theileira equi and Babesia caballi are the causing agents of equine babesiosis. It is a cosmopolitan disease transmitted by ticks present in areas that range 90% of the world equine population. The diagnosis of equine babesiosis might be done laboratorially in its clinical and subclinical forms by direct and indirect methods. In this study the usefulness of four different methodologies of DNA extraction (phenol-chloroform method; CHELEX 100 method; DNAzol® BD Reagent and GFX Genomic Blood DNA Purification Kit) was evaluated using control blood samples. Additionally, blood from 25 apparently healthy horses from the northeast region of São Paulo State (Brazil)was examined for the presence of both T. equi and B. caballi. The phenol-chloroform method showed the best results in extracting babesial DNA. No PCR amplified product was observed in any of the animals tested, although the PCR system was able to detect T. equi and B. caballi DNA in. control blood samples. KEY WORDS: Equine. Theileria equi. Babesia caballi. PCR.