Investigations on Eggs of Helminths, with Special Reference to the Epidemiology of Hydatid Disease

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  • The Center for the Study and Prophylaxis of Hydatid Disease, Montevideo, Uruguay

A search for the oncospheres of Taenia echinococcus is basic to any study of the epidemiology of hydatidosis, but the difficulties of field surveys to find the eggs of helminths as they occur in nature in the soil, in deposited animal feces, on the fur of animals and in dirt sweepings are well known.

There are two general methods of concentrating such material to facilitate the discovery of eggs. The first consists of mixing it with water and allowing the eggs to sink to the bottom where they can be recovered by decanting or filtration. The other method is that of levitation secured by adding solutions of high specific gravity such as saturated salt solution, zinc chloride or alum, in order to float the eggs to the surface from which they can be skimmed.