Antibodies against feline panleukopenia virus, herpesvirus and calicivirus in retrovirus-seropositive cats compared to seronegative cats. In: Clinical/research abstracts accepted for presentation at the AAFP World Feline Conference 2019

Purpose: The aim of this study was to analyse antibody profiles in retrovirus-seronegative and retrovirus-seropositive cats after vaccination or field infection with feline panleukopenia virus (FPV), feline herpesvirus type 1 (FHV-1) and feline calicivirus (FCV). Summary of background/objectives, methods, results and conclusions: Many factors affect response to vaccines or pathogens, including congenital or acquired immunodeficiencies. Retroviral infections with feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) are the most commonly acquired feline immunodeficiencies. Efficacy of vaccination in retrovirus-infected cats is a subject of debate. The study objectives were to identify any differences in antibody profile against field or vaccine FPV, FHV-1 and FCV in retrovirus-seropositive cats as compared with retrovirus-seronegative cats. Frozen archived surplus serum samples from 64 randomly selected retrovirus-seropositive cats (34 FIV+, 23 FeLV+ and 7 FIV+FeLV coinfected cats) and 64 retrovirus-seronegative cats were used in this study. Samples were originally tested for clinical reasons for antibody to FIV target antigens p24 and gp40 and for FeLV p27 antigen using a commercial rapid ELISA kit (SNAP Combo Plus FeLV Ag/FIV Ab). A feline-specific point-of-care ELISA (ImmunoComb, Feline VacciCheck) previously validated for the determination of protective antibody titers (PAT) against FPV, FHV-1 and FCV (1:80, 1:16 and 1:32, respectively) was used to measure antibody titers. Data on signalment (age, breed, sex), origin (owned, shelter, stray), health (healthy/unhealthy) and vaccination status (last trivalent vaccination <3 years, between 3 and 7 years, never accinated, unknown) were statistically compared between retrovirus-seropositive and retrovirus-seronegative cats. No statistically significant differences were observed in the number of FIV+, FeLV+ and FIV+FeLV coinfected cats with PAT for FPV, FHV-1 and FCV compared with retrovirus-seronegative cats (Figure 1 and Table 1). There were significantly fewer young cats (⩽1 year old) (P = 0.0019) in the FIV+ group (0/34) in comparison with retrovirus-seronegative cats (16/64). Unhealthy cats had a higher incidenceof FeLV+ (14/23, P = 0.0193) and FIV+FeLV coinfection (6/7, P = 0.0066) than retrovirus-seronegative cats (21/64). Finally, FIV+FeLV coinfected cats had received fewer (3/7 never vaccinated, P = 0.0215) and less frequent vaccinations (0/7 vaccinated in the past 3 years, P = 0.0057) than retrovirus- seronegative cats (29/64 and 5/64, respectively). Antibody levels against field or vaccine strains of FPV, FHV-1 and FCV in retrovirus-seropositive cats were similar to those in retrovirus-seronegative cats. Based on these results and supporting a recent study in the literature, retrovirus-seropositive cats seem to mount a normal antibody response to common field or vaccine viruses.