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

Abstract

Canine vaccination is the main tool for preventing dangerous and widespread diseases. The strongly recommended (core) dog vaccines are against Canine Parvovirus type 2 (CPV-2), Canine Distemper Virus (CDV), and Canine Adenovirus (CAdV-1), but vaccination protocols should be tailored to dog lifestyles. Vaccination guidelines suggest vaccinating adult dogs no more frequently than every 3 years using modified live (attenuated) vaccines (MLV), thus obtaining a long-lasting (sometimes throughout life) specific protection in many but not all animals. The aim of this study was to determine the actual levels of seroprotection against CPV-2, CDV and CAdV-1 in a cohort of Italian dogs by using the in-practice test VacciCheck. A total of 1,027 dogs (951 vaccinated and 76 unvaccinated) were analyzed for Protective Antibody Titers (PATs) against CPV-2, CDV, and CAdV-1. Differences related to sex, age, breed size, health status, and time elapsed since last vaccination were evaluated. Half of the entire canine cohort (50.6%) had PATs for all three viruses (68.5% considering only vaccinated dogs). In particular, 90.8% of dogs were protected against CPV-2, 68.6% against CDV, and 79.8% against CAdV-1. Most dogs remained protected for 3 years after vaccination or longer. Revaccination on a 3-year basis can then be recommended for core MLV vaccines without altering individual’s seroprotection or even herd immunity.

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

“…This supremacy was likely related to CPV-2 extensive field circulation in rural and urban contexts, and to its well-known environmental resistance and its strong immunogenicity. All of these reasons can explain both the natural booster effect of CPV-2 in vaccinated dogs with high rates of seroprotection, also in the elderly canine population [ 50 , 51 ], and, vice versa, cases of disease in adult and older dogs (sometimes even vaccinated) [ 39 , 59 ]. It should also be considered that cats can be infected with CPV-2 and can shed the virus in the environment with their feces, thus posing a real though uncommon risk to dogs [ 60 , 61 , 62 ].…”

“…This result is not in line with other studies in which smaller dogs better respond to antigenic stimulation and vaccination compared to larger sized dogs [ 38 , 58 , 72 , 73 ]. Furthermore, in our recent study on a cohort of one thousand and twenty-seven Italian dogs [ 50 ], larger dogs have been generally considered less protected than smaller ones. Nevertheless, considering only CPV-2 protection, the peculiarity of more protected larger dogs has been already reported, especially when considering only the nine hundred fifty-one vaccinated animals.…”

“…is another limitation of this study, as this additional information would have helped to better understand and interpret the obtained results. The evaluation of specific vaccine immune response is also incomplete, as it is known that it can stimulate also a strong but not easily measurable cell-mediated immunity [ 50 , 51 , 83 ]. In elderly subjects, however, the aging process particularly affects cell-mediated immunity [ 7 , 15 , 17 , 19 , 20 , 25 , 28 , 29 ], so adding information related to this type of immune response would not add other useful information.…”

“…In this study, results were divided into four categories (unprotected, weak positive, medium positive, and high positive) based on the threshold values of each pathogen, and dogs with antibody titers equal to the different threshold values were considered medium positive. Medium to high positive results were expressed as Protective Antibody Titers (PATs) ( Table S2 ), as already done in our recent previous study [ 50 ] following the suggestions of the literature [ 22 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ].…”

Can Chemotherapy Negatively Affect the Specific Antibody Response toward Core Vaccines in Canine Cancer Patients?

“…The kit is a dot-ELISA-based rapid semi-quantitative system approved to measure the specific antibody titers (IgGs) against CDV, CPV-2, and CAdV-1. VacciCheck has high specificity and sensitivity for each microorganism and is approved to be used for both research and diagnostic purposes [11,15,[27][28][29][30][31][32][33]. In this rapid test, the antibody concentration is defined by the color intensity of the resulting spots compared with a scale from 1 to 6.…”