 Although animals generally express fewer variants of the dicer enzyme than plants, RNAi in some animals produces an antiviral response.In both juvenile and adult "Drosophila", RNA interference is important in antiviral innate immunity and is active against pathogens such as Drosophila X virus.A similar role in immunity may operate in "C. elegans", as argonaute proteins are upregulated in response to viruses and worms that overexpress components of the RNAi pathway are resistant to viral infection.