Epidemiology and co-infection of URTD pathogens in domestic cats during COVID-19

This study investigated the prevalence of upper respiratory tract disease (URTD) pathogens in domestic cats during the SARS-CoV-2 pandemic in southern Brazil, focusing on the detection of feline herpesvirus-1 (FHV-1), feline calicivirus (FCV), Mycoplasma felis, Chlamydia felis, and SARS-CoV-2. A total of 120 cats presenting URTD symptoms and with recent contact (within 15 days) with SARS-CoV-2-positive tutors were analyzed. The detection rates were 38.3% for FHV-1, 34.1% for FCV, 43.3% for M. felis, 19.16% for C. felis, and 1.2% for SARS-CoV-2. Co-infections were common, affecting 64.45% of cases, with M. felis as the most frequent mono-infection and FHV-1 and M. felis as the predominant co-infection. Significant associations were observed between specific host factors and pathogen presence; non-neutered cats and those with outdoor access had higher odds of infection. Retroviral infections (FIV and FeLV) were found to increase susceptibility to URTD agents, particularly C. felis and FCV. Clinically, sneezing and nasal discharge were prevalent in over 90% of cases, and conjunctivitis was strongly linked to C. felis and FHV-1. Despite concerns surrounding the zoonotic potential of SARS-CoV-2 during the COVID-19 pandemic, the virus played a limited role, as only one cat tested positive for SARS-CoV-2 RNA. These findings emphasize the importance of focusing on established URTD pathogens for feline health management, even amid global health events.