Molecular epidemiology of feline calicivirus (FCV) and felid alphaherpesvirus 1 (FeAHV-1) in cats with clinical signs and clinically healthy cats

Feline Calicivirus (FCV) and Felid Alphaherpesvirus 1 (FeAHV-1), commonly detected in cats, are significant viral pathogens causing upper respiratory tract disease (URTD) and various clinical signs. Co-infection with both viruses is common and a major problem in feline health worldwide. This study investigated the presence and prevalence of both FCV and FeAHV-1 in suspected cats with either clinically healthy or clinical signs in relation to various parameters related to the sampled animals. A total of 331 diagnostic samples (conjunctival, nasal, and oropharyngeal swabs, and EDTA blood samples) were collected from 107 cats and examined using PCR. FCV nucleic acid was detected in cats 33.64 % (36/107), while FeAHV-1 nucleic acid was found 64.48 % (69/107). Of the cats with clinical signs (n = 31), 48.38 % (15/31) and 74.19 % (23/31) were positive for FCV and FeAHV-1, respectively, while 27.63 % (21/76) and 60.52 % (46/76) of the clinically healthy cats (n = 76) were positive for FCV and FeAHV-1, respectively. The overall positivity rates for FCV and FeAHV-1 were 90.32 % (28/31) in cats with clinical signs and 72.36 % (55/76) in clinically healthy cats, respectively. Additionally, 20.33 % (12/59) of vaccinated cats were positive for FCV and 64.40 % (38/59) for FeAHV-1, whereas 48.88 % (22/45) of unvaccinated cats were positive for FCV and 66.67 % (30/45) for FeAHV-1. The results indicate that both infections are prevalent among clinical and/or clinically healthy, vaccinated/unvaccinated cats. This indicates that clinically healthy cats may play a significant role in the epidemiology of these infections, and that vaccination may not provide complete protection against FCV and FeAHV-1 infection.