Burden of Common Respiratory Pathogens Among Cats in China.

Background: Feline respiratory disease complex (FRDC) is a set of illnesses which are primarily associated with different types of viruses and bacteria. There is scarcity of data on pathogens associated with FRDC in China.

Objectives: The primary objective of this study was to investigate the prevalence and dynamics of FRDC pathogens in China.

Methods: A total of 458 samples were retrieved from veterinary clinics during 2021-2024 from cats suffering from respiratory infections. Four viruses and three bacteria associated with FRDC were targeted for molecular detection with real time qPCR/RT-qPCR assays.

Results: At least 1 targeted respiratory pathogen was detected in 423 samples (92.3%), whereas no pathogens were detected in 7.7% of samples. Bacteria were detected in 32.1% of samples, and viruses were detected in 60.2% of samples. The prevalence of viruses detected were feline calicivirus (31.2%), feline herpesvirus-1 (24.6%), influenza A virus (2.8%) and severe acute respiratory syndrome coronavirus-2 (1.5%), whereas the detection rate for bacteria was Mycoplasma felis (15.5%), Chlamydia felis (10.2%) and Bordetella bronchiseptica (6.3%). Significantly higher cases were reported from kittens (57.4%). Pathogen detection was more common during the cold season. Mono-infections involving one bacteria or virus were detected in 44.7% of samples, whereas coinfections were detected in 47.5% of samples. No quadruple coinfections were recorded in this study.

Conclusions: The frequency of detection of feline respiratory pathogens alone or in combinations among diseased cats was high, indicating a heavy burden of respiratory infections among cats in Kunshan, China. Continued surveillance is desired, and newly emerged respiratory pathogens should also be monitored in routine diagnostic testing.