The present invention relates to flea peritrophin proteins; to flea peritrophin nucleic acid molecules, including those that encode such flea peritrophin proteins; to antibodies raised against such proteins; and to compounds that inhibit the activity of such proteins. The present invention also includes methods to obtain and use such proteins, nucleic acid molecules, antibodies, and inhibitory compounds. The present invention also includes therapeutic compositions comprising such inhibitory compounds, particularly those that specifically inhibit flea peritrophin activity, as well as the use of such therapeutic compositions to treat animals.