Principais agentes etiológicos envolvidos nas doenças do trato respiratório superior felino na região da Serra Gaúcha

Abstract

Feline upper respiratory tract disease (URTD) is a highly contagious condition that primarily affects stray cats, shelter cats, and those living in high-density environments. Its severity is exacerbated by factors such as stress, poor hygiene conditions, and co-infections that contribute to immunosuppression. The main etiological agents include feline herpesvirus-1 (FHV-1), feline calicivirus (FCV), Chlamydophila felis (C. felis), and Mycoplasma felis (M. felis). In recent years, SARS-CoV-2 has emerged as a pathogen of interest in the human-animal interface, raising concerns about its impact on feline health. This study aimed to review the major pathogens involved in feline URTD, including both traditional and emerging agents, with an emphasis on zoonotic potential and the One Health concept. In addition to a theoretical review, we conducted an experimental study during the COVID-19 pandemic, analyzing 120 cats through clinical sample collection and detailed anamnesis. Molecular diagnosis was performed using RT- qPCR for SARS-CoV-2 and conventional PCR for the other pathogens. Our findings revealed a high rate of co-infections (68.4%), with the FHV-1 + M. felis combination significantly associated with increased clinical severity. Sneezing and nasal discharge were observed in 90% of symptomatic animals, reinforcing the clinical impact of URTD. Outdoor access significantly increased the risk of infection, while immunosuppression due to retroviruses (FIV and FeLV) was also an important predisposing factor, particularly given the large population of retrovirus-positive cats. Unvaccinated cats accounted for 60% of the animals infected with at least one pathogen, highlighting the need for more effective immunization strategies. The prevalence of SARS-CoV-2 was low (0.8%), with only one positive case, suggesting that despite potential zoonotic risk, sustained transmission in domestic cats does not appear to be significant. These findings underscore the need for integrated diagnostic approaches and highlight the importance of the One Health concept in understanding infectious disease dynamics between felines and humans. Additionally, the high frequency of co-infections and their correlation with clinical severity suggest the need for revised therapeutic and management strategies. Future perspectives include genetic sequencing of involved pathogens and the development of updated vaccines incorporating circulating field strains to enhance URTD control and reduce morbidity in vulnerable feline populations. [resumo fornecido pelo autor]