**4.9 Immunochromatographic (IC) assays**

IC assays or Lateral flow assays are strip-based devices utilized for the detection of a target analyte in test samples. Colloidal gold nanoparticles are commonly used in synthesis of the probe (conjugate) in majority of these strip-based points of care assays. Different components used are the sample pad, conjugate pad, nitrocellulose membrane, absorbent pad and a plastic cassette. These tests are now used routinely for the parvovirus diagnosis in affected dogs. A number of lateral flow assay-based commercial kits are available for rapid detection of both CPV-2 antigen in feces and antibodies in

serum, which are also available in the market. These are helpful in the field and gives rapid results within 10–15 mins. Recombinant VP2 protein based immunochromatography tests has also been developed based on the rapid detection of CPV-2 [62].

## **4.10 Dot blot/dot-ELISA**

It is an immunological test which uses charging of test antigen on to a nitrocellulose or PVDF membrane followed by detection using specific antibody against the antigen and an enzyme labeled secondary antibody which forms a color on addition of an insoluble substrate. It is helpful as on the spot assay for CPV diagnoses. It has been developed for detection of CPV-2 using hyperimmune sera raised against the whole virus/recombinant VP2 protein. Commercial dot ELISA kits are also available for evaluating IgM response against CPV-2 after vaccination or infection [63].
