The present invention provides new compositions and methods for preventing andtreating pathogen infection. In particular, the present invention providescompounds having an anchoring domain that anchors the compound to the surfaceof a target cell, and a therapeutic domain that can act extracellularly toprevent infection of the target cell by a pathogen, such as a virus. Preferredtarget cells are epithelial cells. The invention provides compositions andmethods for preventing viral diseases, such as influenza, using compoundshaving anchoring domains that can bind target cells linked to enzymaticactivities that can act extracellularly to interfere with viral infection oftarget cells. The invention also provides compositions and methods forpreventing viral diseases such as influenza using compounds having anchoringdomains that can bind target cells linked to protease inhibitors that can actextracellularly to interfere with viral infection of target cells.
