A study on Feline Upper Respiratory Tract Disease with Clinico-molecular Profiling of the associated Feline Herpesvirus and Calicivirus Infections in Domestic Cats

This cross-sectional study aimed to investigate feline upper respiratory tract disease (FURTD) in domestic cats, with a focus on the associated feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1). To the best of our knowledge, there are no previous studies on FCV in domestic cats in Egypt, and studies on FHV-1 are very limited. A total of 850 cats were included, signs of FURTD were detected in 101 cats in a percentage of 11.9%. Significant variations were existed among different ages and breeds. PCR targeting FHV-1 and RT-PCR targeting FCV were performed for 30 diseased cats and showed ten and eleven positive cases in a percentage of 33.3% and 36.7%, respectively. Most of the molecular identified cases existed as a singleton infection, except of two cases of mixed infection in a percentage of 6.7%. Obvious respiratory signs were detected for both viruses with a notable ocular involvement of FHV-1 infected cases and Oral lesions and tongue ulcers of FCV infected cases. Five FHV-1 strains and three FCV strains were sequenced for phylogenetic analysis on both the genomic and protein levels which are presented in the results section. In conclusion, FURTD is prevalent among cats in the study area and FHV-1 and/or FCV infection exists in a considerable proportion of these cases which are associated with variable clinical signs and case fatality rates. In addition, phylogenetic analysis is important for traceability and detection of relationship between these pathogens.