(Russian dezinvaziia, from dez- and Latin invasio, attack), destruction in the external environment of embryonic elements (eggs and larvae of helminths and oocysts of coccidia, for example) of the causative agents of parasitic diseases of humans, animals, and plants. Among the means used to accomplish this are the mechanical (tidying up, cleaning, and washing premises and replowing the land), physical (fire, dry heat, steam, sunlight, and ultraviolet radiation), chemical (wood naphtha, iodine monochloride, carbathione, and caustic soda), and biological. To determine the effectiveness of disinfestation, test samples (scrapings) are taken from various sections of the object, embryonic elements are isolated from them by appropriate methods, and the viability of the elements is determined by culturing in an incubator, by microscopy, or by biological testing.