method of serology that detects antibodies for diagnostic purposes. Western blot (immunoblot assay) and enzyme-linked immunosorbent assay (ELISA) are two other methods used to detect proteins (or antigens) in serum. In each of these techniques, the antibodies for the protein of interest are added and the presence of the specific protein is indicated by a color change. ELISA was shown to have higher sensitivity to the HEF than the HI test. Because only Influenza viruses C and D produce esterase, In Situ Esterase Assays provide a quick and inexpensive method of detecting just Types C and D. If more individuals were tested for Influenza virus C as well as the other three types, infections not previously associated with Type C may be recognized. Vaccination Because influenza virus A has an animal reservoir that contains all the known subtypes and can undergo antigenic shift, this type of influenza virus is capable of producing pandemics. Influenza viruses A and B also cause seasonal epidemics almost every year due to their ability to antigenic drift. Influenza virus C does not have this capability and it is not thought to be a significant concern for human health. Therefore, there are no vaccinations against influenza virus C. References Further reading ICTVdB database for Influenza viruses External links Influenza Research Database Database of influenza genomic sequences and related information. Viralzone: Influenza virus C Orthomyxoviridae Influenza de:Influenzavirus#Influenza-C-Subtypen