The invention relates to double-stranded ribonucleic acids (dsRNAs) targeting gene expression of phosphatidylinositol 4-kinase (P14K), in particular human phosphatidylinositol 4-kinase, catalytic, beta polypeptide (PIK4CB) or human phosphatidylinositol 4-kinase, catalytic, alpha polypeptide (PIK4CA), and their use for treating infection by positive stranded RNA viruses such as hepatitis C virus (HCV). Each dsRNA comprises an antisense strand having a nucleotide sequence which is less that 30 nucleotides in length, generally 19-25 nucleotides in length, and which is substantially complementary to at least a part of the PIK4CB or PIK4CA target mRNA. A plurality of such dsRNA may be employed to provide therapeutic benefit. The invention also relates to a pharmaceutical composition comprising the dsRNA together with a pharmaceutically acceptable carrier, and including a delivery modality such as fully encapsulated liposomes or lipid complexes. The invention further includes methods for treating diseases caused by positive stranded RNA virus infection using the pharmaceutical compositions； and methods for inhibiting the propogation of positive stranded RNA viruses in and between cells.
