Canine Distemper Virus Antibody Test (IFA)
Canine Distemper virus is in the family of paramyxovirus. The virus infects many species of carnivores including lions and some marsupials. The dog is the primary host and puppies from 3 to 6-months old are at most risk. The virus infects primarily the lymphoid, epithelial, and nervous tissues. Initial infection usually occurs in lymphatic tissue of the respiratory tract. The virus enters the blood stream and infects respiratory, gastrointestinal, urogenital epithelial cells along with central nervous system and optic nerves. Typical pathologies include lymphoid depletion (immunosuppression), pneumonia, encephalitis, and hyperkeratosis of nose and footpad. Vaccinated dogs are well protected and vaccine IFA titers range from 1:10 to 1:200 depending on the quality of the vaccine. IFA titers of 1:25 and above is correlated with protective levels of virus neutralizing antibody.
Our test for Canine Distemper Antibodies is an indirect fluorescent antibody (IFA) procedure that is carried out on Teflon matted slides that contain fixed virus infected cells (MA/84 virus in mink lung cells). This method requires the use of diluted patient serum being placed on the slide and incubated for 30-minutes at which time the slide is washed and a fluorescein conjugated anti-dog globulin is placed on the slide. If any antibodies to CDV are present in the patient serum they will combine with the CDV antigen fixed to the slide surface. The fluorescent antibody conjugate will then be bound to the CDV antibodies and the resulting antibody-conjugate complex viewed with an ultraviolet microscope are seen as bright areas of fluorescence in the infected cells. The total number of infected cells on our slides does not exceed 40% which leaves the negative cells to enhance contrast.