Extraction and recovery technique for myxozoan parasites from the Piaractus mesopotamicus kidney embedded in paraffin

Resumo

Tissues fixed and embedded in paraffin for histopathological studies keep their cell characteristics. There are several protocols for extracting genetic material from tissue embedded in paraffin, but there is no protocol for material aimed at the direct identification of parasites. The lack of techniques which describe the recovery of parasites from tissue embedded in paraffin has led us to test a technique for recovering myxosporean parasites found in Piaractus mesopotamicus kidney fragments embedded in paraffin, for a rapid, direct, and economic identification. Once the excess paraffin was removed from the kidney fragment, this was deparaffinized in xylene, hydrated in 70% alcohol, placed in an Eppendorf tube containing 70% alcohol, and left under vigorous and constant agitation in a vortex until the tissue was disintegrated. The precipitated material was mixed with the 70% alcohol and 20 µL were collected for preparing the smears, which were stained with Giemsa. Myxobolus sp. spores at many developmental stages were observed by light microscopy. The technique has proved to be useful for recovering myxosporean parasites from tissue embedded in paraffin and it constitutes an effective tool for prevalence studies when the myxosporean parasites are not detected in fresh mounts.