References
Persistent feline coronavirus infection in a cat with cardiac and gastrointestinal signs
Abstract
Background
Feline coronavirus infection causes feline infectious peritonitis in a subset of cats, but can also result in persistent infection. The tissue reservoirs of feline coronavirus and the role of viral persistence in pathogenesis are poorly understood.
Aims
This study aimed to identify sites of feline coronavirus persistence in a naturally infected cat, identify disease correlates and characterise within-host viral evolution.
Methods
The study followed a 5-year-old Bengal cat for 6 years and collected non-invasive samples, including faeces and conjunctival, oropharyngeal and saliva swabs. At 11-years-old, the patient was euthanised as a result of respiratory distress, and tissue samples were collected. The authors used hybridisation capture and next-generation sequencing methodologies focused on the feline coronavirus S gene, along with RNA in-situ hybridisation.
Results
During the study, the patient was diagnosed with inflammatory bowel disease, alimentary small cell lymphoma, chronic rhinitis and mitral valve regurgitation. Feline coronavirus was detected in the nasal cavity, intestine, faeces and conjunctiva in 2017, and in the intestine, faeces and heart in 2022. Sequence analysis showed that the virus adapted to tissue reservoirs over time.
Conclusions
This study identifies potential feline coronavirus reservoirs. The relationship of persistent feline coronavirus infection to chronic conditions warrants further investigation.
Feline coronavirus is a common and highly transmissible infection of cats. Consistent with the first clinical report (Holzworth, 1963), a recent phylogeographic study indicated that feline coronavirus type 1 (by far the most prevalent of the two viral genotypes) emerged in the United States between the 1950s and the 1970s, followed by rapid spread world-wide (Lauzi et al, 2020). It is now endemic everywhere that cats are housed in groups. Transmission is generally considered to be faecal-oral, leading to infection of enterocytes and causing mild and self-limiting gastroenteritis. While enterocytes appear to be the primary target of infection, a monocyte-associated viraemia is common, even in healthy animals (Gunn-Moore, 1998; Can Sahna, 2007). In a small subset of cats, feline coronavirus gains the ability to productively infect monocytes and tissue macrophages, triggering systemic vasculitis. This form of feline coronavirus infection, known as feline infectious peritonitis, is historically fatal; however, recent advances in the development of antivirals have led to rapid advances in the treatment of this otherwise lethal disease (Coggins et al, 2023).
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