Comparison of Methods of Examining Stools for Parasites

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  • Unidad de Patología, Escuela de Medicina, Universidad Nacional Autónoma de México (Hospital General)


Simultaneous fecal examinations were made of 400 samples by the following methods: direct, Faust, Bayona, Ferreira and Baermann; 103 samples were negative and in the remainder, 18 species of parasites were found. The direct method is indispensable for the finding of trophozoites. For cysts, eggs and larvae, the Ferreira method diagnosed a greater number of positive samples than the other methods. It was particularly effective when the number of eggs was small, providing richer concentrations. However, irregularity of excretion, particularly of cysts, makes more than one examination necessary.