Plays a role in host liquefaction to facilitate horizontal transmission of the virus by hydrolyzing beta-chitin and by regulating the cysteine protease VCATH. Localized in the host reticulum endoplasmic via its KDEL motif, interacts with and thus prevents VCATH secretion before host cell lysis occurs. Random endo-hydrolysis of N-acetyl-beta-D-glucosaminide (1->4)-beta-linkages in chitin and chitodextrins. Interacts with host VCATH. Belongs to the glycosyl hydrolase 18 family. Chitinase class II subfamily.