Agreement between In-Clinics and Virus Neutralization Tests in Detecting Antibodies against Canine Distemper Virus (CDV)

Abstract

Core vaccinations and specific antibody titer evaluations are strongly recommended worldwide by all the vaccination guidelines. Virus neutralization (VN) is considered the gold standard for measuring antibody titer against canine distemper virus, but it is complex and time consuming, and the use of in-clinics tests would allow to obtain quicker results. The aim of this study was to evaluate the agreement of the commercial in-clinics VacciCheck test compared to VN. A total of 106 canine sera were analyzed using both methods. The best agreement was obtained using a protective threshold of ≥1:32. VacciCheck showed 95.5% sensitivity, 87.2% specificity, and 92.5% accuracy. The Cohen’s kappa coefficient between methods was 0.84 (CI 95% 0.73 to 0.95), revealing an optimal agreement between the two methods (p = 0.0073). The evaluation of discordant results reveal that most samples had less than 1.5 dilution difference, and that usually did not affect the classification as protected or non-protected. Results also suggest that, in dubious cases, especially when a protective result is expected, retesting is advisable. In conclusion, VacciCheck may be considered as a reliable instrument that may help the clinician in identifying the best vaccine protocol, avoiding unnecessary vaccination, and thus reducing the incidence of adverse effects.

Prevalence of Serum Antibody Titers against Core Vaccine Antigens in Italian Dogs

“…For these reasons, PATs against CDV are lower than CPV-2 ones. It should, however, be considered that, based on its performance studies, VacciCheck considers as positive values those greater than or equal to the threshold of 1:32 [ 46 , 63 ], while other in-clinic tests and some laboratories that perform the gold standard tests suggest using a threshold of a 1:16. This means that dogs considered unprotected in this study with a titer of 1:16 could instead be considered protected if the threshold value was lowered to 1:16 by raising the final percentage of CDV protection to 87.9% (instead of 68.6%).…”

“…The kit is a rapid semiquantitative dot-ELISA-based system licensed to determine the antibody titers against CPV-2, CDV, and CAdV-1. The test has been previously validated, showing good values of specificity and sensitivity for each pathogen and can be applied in practice, as indicated in the WSAVA guidelines and in many other studies [ 1 , 2 , 34 , 43 , 44 , 45 , 46 ].…”

Effect of Aging on the Immune Response to Core Vaccines in Senior and Geriatric Dogs

“…VacciCheck ® is a rapid semiquantitative dot-ELISA-based kit able to determine specific antibody titers against CPV-2, CDV, and CAdV-1 in serum, plasma, or whole blood of dogs. This test has good specificity and sensitivity for each virus and can be very useful in daily veterinary practice to evaluate the real protection of dogs (and cats) against diseases preventable by core vaccines, as suggested by the international vaccination guidelines and by many other studies [ 1 , 33 , 45 , 46 , 47 , 48 , 49 ]. In this test, the antibody concentration is directly proportional to the color intensity of the related spots read by the CombScale and expressed as “S” units on a scale from 1 to 6.…”

2024 guidelines for the vaccination of dogs and cats – compiled by the Vaccination Guidelines Group (VGG) of the World Small Animal Veterinary Association (WSAVA)

“…An advance in companion animal practice is the commercial availability of in‐practice diagnostic test kits that can detect antibodies against CDV, CPV and CAV in dogs and FPV in cats. Some of these test kits have been validated for use in practice and shelter settings and are simple to use (Egerer et al., 2022; Gray et al., 2012; Litster et al., 2012; Meazzi et al., 2022). They provide a rapid result (positive or negative) within 20 to 30 minutes.…”

“…In‐practice serological test kits have gained favour with some veterinarians who wish to offer their clients a convenient alternative to routine revaccination at (for example) 3‐yearly intervals. However, in‐practice serological test kits have been shown to vary in sensitivity, specificity, positive and negative predictive value (PPV and NPV), and overall accuracy (OA) when compared to reference, gold standard tests (Bergmann et al., 2020; Bergmann, Halzheu, et al., 2021a; Bergmann, Zablotski, et al., 2021b; Dall'Ara et al., 2021; DiGangi, Gray, et al., 2011a; Egerer et al., 2022; Meazzi et al., 2022; Mende et al., 2014).…”