ORIGINAL RESEARCH article
Front. Vet. Sci.
Sec. Veterinary Infectious Diseases
Volume 12 - 2025 | doi: 10.3389/fvets.2025.1542397
Seroprevalence of SARS-CoV-2 in Cats from COVID-19 Positive Households in the Lisbon Area
Provisionally accepted
Frederico Nuno C. Aires Da Silva1,2,3*
Isa Moutinho2,3
Sara Cardoso2,3Mafalda Henriques2,3
Joao Goncalves4
Solange Gil2,3Luis Tavares2,3Telmo Nunes2,3- 1University of Lisbon, Lisbon, Portugal
- 2Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisboa, Lisboa, Portugal
- 3Associate Laboratory for Animal and Veterinary Sciences, Lisbon, Portugal
- 4Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal, Lisbon, Portugal
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Since the onset of the COVID-19 pandemic, the transmission of SARS-CoV-2 between humans and cats has been well-documented. However, the dynamics of this cross-species transmission remain insufficiently understood. Seroprevalence studies in cat populations across different contexts and regions are crucial for estimating viral infection rates and tracking viral evolution. Furthermore, identifying risk factors associated with human-to-cat transmission is essential. This study, conducted during the COVID-19 pandemic, assessed SARS-CoV-2 transmission and seroprevalence in 76 cats from COVID-19-positive households in the Lisbon area. Of these, 23 (30.3%) tested positive for antibodies against SARS-CoV-2 variants (alpha, delta and omicron) using enzyme-linked immunosorbent assay (ELISA). Among the ELISA-positive samples, 16 (69.6%) exhibited potent neutralizing antibodies confirmed via surrogate virus neutralization tests (sVNT) and pseudotyped viruses assays. Compared to our previous study of cats with unknown exposure to SARS-CoV-2 in the Lisbon area, this study found significantly higher rates of seroprevalence (30.3% vs. 14.7%) and neutralizing antibody prevalence (69.6% vs. 20.4%) in cats from COVID-19-positive households, suggesting greater exposure and infection risk in these settings. To identify risk factors for human-tocat SARS-CoV-2 transmission, we analyzed the association between animal characteristics, cat-owner interactions, owner clinical signs, and sVNT results. None of the risk factors studied showed a statistically significant association with seropositivity in cats. Future studies should further investigate the impact of demographic characteristics, health conditions, lifestyle, owner-cat interactions, and owners' symptoms during infection to better understand their role in SARS-CoV-2 transmission from humans to cats and to inform strategies for controlling future outbreaks.
Keywords: SARS-CoV-2, COVID-19, human-to-cat transmission, Antibodies, One Health
Received: 09 Dec 2024; Accepted: 28 May 2025.
Copyright: © 2025 Silva, Moutinho, Cardoso, Henriques, Goncalves, Gil, Tavares and Nunes. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Frederico Nuno C. Aires Da Silva, University of Lisbon, Lisbon, Portugal
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