Therapeutic options for cats with CRS mentioned in the literature include: antibiotics, antihistamines, oral decongestants (e.g., diphenhydramine hydrochloride), non-steroidal anti-inflammatory drugs, glucocorticoids, leukotriene blockers (e.g., montelukast), and immunotherapy (e.g., lipid–DNA complexes encoding the feline interleukin-2 gene) (14). This evidence concerns the gene IL2 and congenital rubella syndrome.