Coloración de azul de metileno como alternativa para determinar la viabilidad de larvas libres de Trichinella spiralis

the present research was carried out with the purpose of determining whether or not the methylene blue test could also evidence viability of free larvae of trichinella spiralis, taking into account its usefulness in the determination of viability of protoscolices in echinococcus granulosus. to this end, three t. spiralis larval suspensions (m1, m2 and m3) were used, each containing 500 free larval stages. a hundred μl of methylene blue solution 1:10000 in distilled water were added to 100 μl of the larval suspension. larvae were observed under optical microscopy to evaluate motility. m1 was exposed to -30 °c and could be observed on day 70, m2 was exposed to 80 °c during 5 minutes and it was immediately observed under optical microscopy, and m3 was maintained at 4 °c during the experiment as a 100% viability testing. our results indicated that when t. spiralis larvae took up 100% of the methylene blue stain (m1 and m2), their inner structures appeared not only retracted but also stained blue, whereas in the m3 suspension test, larvae remained unstained and 100% of them showed their typical spiral-like movement.