The Retention of Endamoeba Histolytica Cysts Under Finger-Nails

View More View Less
  • Department of Protozoölogy of the School of Hygiene and Public Health of the Johns Hopkins University, Baltimore, Maryland

In a recent report by Spector and Buky (1934), it is indicated that cysts of Endamoeba histolytica in feces exposed upon the surface of the fingers rarely survived air drying under ordinary laboratory conditions for more than five minutes. The criterion of viability was the alteration of cell-wall permeability to a 1:1000 aqueous solution of eosin. The technique in these experiments was to liberally contaminate the fingers or thumbs either by smearing them with or dipping them into feces or a homogeneous fecal emulsion containing amoebic cysts or trophozoites. After various exposure periods, the contaminated surfaces were washed into sterile distilled water or saline solution, which was then slowly centrifuged. The sediment was examined in an equal volume of eosin solution and the stained and unstained organisms were enumerated.