Abstract: A method for externally eradicating by inactivation infectious pathogenic contaminants in body tissues, such as blood, so that it can be introduced into an animal comprises admixing the body tissues with an effective, non-toxic, amount of a photoactive agent which selectively binds to the contaminant, passing the resulting mixture through an irradiation chamber, and then irradiating the resulting mixture with an effective level of visible light for an effective period of time to eradicate the contaminants.

Abstract: A method of treating a body fluid so as to inactivate protozoa in said fluid comprises mixing the body fluid with an effective amount of a photosensitizing agent which will bind to cell-free protozoa and/or protozoan-infected cells, and then exposing the resulting mixture to visible light to inactivate the protozoa. An apparatus for use in the method includes at least one container which contains a body fluid containing protozoa and an effective amount of a photosensitizing agent to bind to the protozoa. The apparatus has at least one wall which is permeable to visible light.