A method for preparing a pharmaceutical composition, comprising: (a) providing a sialidase catalytic domain protein comprising a catalytic domain of a sialidase, wherein the protein comprises a catalytic domain sequence selected from: (i) the sequence of amino acids set forth in SEQ ID NO:14, wherein said sequence lacks amino acids 1 to 273 of the sequence any of the amino acids set forth in SEQ ID NO.12; (ii) an amino acid sequence that begins at amino acid 274 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 666 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 273 and 667 to 901 of the sequence of amino acids set forth in SEQ ID NO: 12; (iii) an amino acid sequence that begins at amino acid 274 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 681 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 273 and 682 to 901 of the sequence of amino acids set forth in SEQ ID NO.12; (iv) an amino acid sequence that begins at amino acid 290 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 666 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 289 and 667 to 901 of the sequence of amino acids set forth in SEQ ID NO: 12; and (v) an amino acid sequence that begins at amino acid 290 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 681 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 289 and 682 to 901 of the sequence of amino acids set forth in SEQ ID NO:12, wherein the sialidase catalytic domain protein has sialidase activity; and (b) combining the sialidase catalytic domain protein with a pharmaceutically acceptable carrier or diluent thereby creating a pharmaceutical composition. (a) providing a sialidase catalytic domain protein comprising a catalytic domain of a sialidase, wherein the protein comprises a catalytic domain sequence selected from: (i) the sequence of amino acids set forth in SEQ ID NO:14, wherein said sequence lacks amino acids 1 to 273 of the sequence any of the amino acids set forth in SEQ ID NO.12; (ii) an amino acid sequence that begins at amino acid 274 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 666 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 273 and 667 to 901 of the sequence of amino acids set forth in SEQ ID NO: 12; (iii) an amino acid sequence that begins at amino acid 274 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 681 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 273 and 682 to 901 of the sequence of amino acids set forth in SEQ ID NO.12; (iv) an amino acid sequence that begins at amino acid 290 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 666 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 289 and 667 to 901 of the sequence of amino acids set forth in SEQ ID NO: 12; and (v) an amino acid sequence that begins at amino acid 290 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 681 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 289 and 682 to 901 of the sequence of amino acids set forth in SEQ ID NO:12, wherein the sialidase catalytic domain protein has sialidase activity; and (i) the sequence of amino acids set forth in SEQ ID NO:14, wherein said sequence lacks amino acids 1 to 273 of the sequence any of the amino acids set forth in SEQ ID NO.12; (ii) an amino acid sequence that begins at amino acid 274 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 666 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 273 and 667 to 901 of the sequence of amino acids set forth in SEQ ID NO: 12; (iii) an amino acid sequence that begins at amino acid 274 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 681 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 273 and 682 to 901 of the sequence of amino acids set forth in SEQ ID NO.12; (iv) an amino acid sequence that begins at amino acid 290 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 666 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 289 and 667 to 901 of the sequence of amino acids set forth in SEQ ID NO: 12; and (v) an amino acid sequence that begins at amino acid 290 of the sequence of amino acids set forth in SEQ ID NO: 12 and ends at amino acid 681 of the sequence of amino acids set forth in SEQ ID NO: 12, and lacks amino acids 1 to 289 and 682 to 901 of the sequence of amino acids set forth in SEQ ID NO:12, (b) combining the sialidase catalytic domain protein with a pharmaceutically acceptable carrier or diluent thereby creating a pharmaceutical composition.