Rabies,
canine distemper, and canine parvovirus are common contagious
viral diseases of dogs and many other carnivores, and pose a severe threat to the population dynamics of wild carnivores, as well as endangering carnivore conservation. However, clinical diagnosis of these diseases, especially
canine distemper and canine parvovirus, is difficult because of the broad spectrum of symptoms that may be confused with other respiratory and enteric diseases of dogs. The most frequently used and proven techniques for diagnosing
viral diseases include the conventional
enzyme-linked
immunosorbent assay (ELISA), rapid fluorescent focus inhibition test (RFFIT), mouse neutralisation test (MNT), and fluorescent antibody virus neutralization (FAVN) test. However, these methods still have some inherent limitations. In this study, a magnetic
protein microbead-aided indirect fluoroimmunoassay was developed to detect canine virus specific
antibodies, human
rabies immunoglobulin, CDV McAbs, and CPV McAbs. In this assay, an
avidin-
biotin system was employed to combine magnetic
microbeads and virus
antigens (rabies virus, canine distemper virus, and canine parvovirus). Quantification of the targeted virus
antibodies was analyzed through indirect fluoroimmunoassay using the specific antigen-antibody reaction, as well as their corresponding
FITC-labeled detection
antibodies (mouse anti-human
IgG/
FITC conjugate or rabbit anti-dog
IgG/
FITC conjugate). The results indicated that the fluorescence intensity increased when a higher concentration of the targeted analyte was used, but the control had almost no fluorescence, much like the conventional ELISA. For human
rabies immunoglobulin, CDV McAbs, and CPV McAbs, the minimum detectable concentrations were 0.2 IU/mL, 0.3 ng/mL, and 0.5 ng/mL, respectively. All of these results indicate that this assay can be employed to determine the presence of canine virus specific
antibodies. In addition, the method devised here can be utilized as a general protocol in other bacterial and
viral marker analysis.