In infection with flaviviruses such as Zika, dengue, and West Nile virus, XRN1 is stalled and blocked from continuing degradation at the site of the viral mRNA 3′ untranslated region (3′-UTR) due to the presence of pseudoknots or stem loops, which are referred as XRN1-resistant structures (xrRNAs). This evidence concerns the gene XRN1 and infection.