Efek hambatan dan viabilitas sel virus dengue serotipe 2 Strain New Gueina C oleh senyawa murni katekin terhadap sel vero pada mekanisme pre-post infeksi dan post-infeksi = The effect of resistance and cell viability of dengue virus serotype 2 New Gueina C strains by pure catechin compound on vero celss during pre-post infection and post infection