Similarly, higher transcriptional expression of crp genes was observed in common carp treated with polyinosinic:polycytidylic acid (polyI:C, a compound that mimics viral dsRNA)36, in DNA-vaccinated rainbow trout (Oncorhynchus mykiss)44 and zebrafish (Danio rerio) embryos microinjected with an expression plasmid encoding the il6 gene42, a cytokine that is upregulated in response to viral infections in humans45. Here, CRP is linked to viral infectious disease.