Diagnostic Value of Detecting Feline Coronavirus RNA and Spike Gene Mutations in Cerebrospinal Fluid to Confirm Feline Infectious Peritonitis.

Sandra Felten,Stefanie Dörfelt,Kaspar Matiasek,Laura Sangl,Christian M Leutenegger,Katrin Hartmann,Andrea Fischer,Stephanie Herre

doi:10.3390/v13020186

Sandra Felten, Stefanie Dörfelt + Show 6 more

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https://doi.org/10.3390/v13020186

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Abstract

Background: Cats with neurologic feline infectious peritonitis (FIP) are difficult to diagnose. Aim of this study was to evaluate the diagnostic value of detecting feline coronavirus (FCoV) RNA and spike (S) gene mutations in cerebrospinal fluid (CSF). Methods: The study included 30 cats with confirmed FIP (six with neurological signs) and 29 control cats (eleven with neurological signs) with other diseases resulting in similar clinical signs. CSF was tested for FCoV RNA by 7b-RT-qPCR in all cats. In RT-qPCR-positive cases, S-RT-qPCR was additionally performed to identify spike gene mutations. Results: Nine cats with FIP (9/30, 30%), but none of the control cats were positive for FCoV RNA in CSF. Sensitivity of 7b-RT-qPCR in CSF was higher for cats with neurological FIP (83.3%; 95% confidence interval (95% CI) 41.8–98.9) than for cats with non-neurological FIP (16.7%; 95% CI 6.1–36.5). Spike gene mutations were rarely detected. Conclusions: FCoV RNA was frequently present in CSF of cats with neurological FIP, but only rarely in cats with non-neurological FIP. Screening for spike gene mutations did not enhance specificity in this patient group. Larger populations of cats with neurological FIP should be explored in future studies.

Highlights

Feline coronaviruses (FCoV) are enveloped RNA viruses belonging to the genusAlphacoronavirus within the family Coronaviridae
Sensitivity of 7b-RT-qPCR in cerebrospinal fluid (CSF) was higher for cats with neurological feline infectious peritonitis (FIP) (83.3%; 95% confidence interval 41.8–98.9) than for cats with non-neurological FIP (16.7%; 95% CI 6.1–36.5)
feline coronavirus (FCoV) RNA was detected by 7b gene RT-qPCR in the CSF from nine of the 30 cats with FIP: five cats with neurologic FIP (5/6, 83%) and four cats with non-neurologic FIP (4/24, 17%) (Table 1)

Summary

Introduction

Feline coronaviruses (FCoV) are enveloped RNA viruses belonging to the genusAlphacoronavirus within the family Coronaviridae. In a small percentage of cats, feline infectious peritonitis (FIP) develops secondary to mutation of non-pathogenic FCoV of serotype I or II to a highly pathogenic biotype within an infected cat [3,4]. This biotype, in contrast to non-pathogenic FCoV with a tropism for enterocytes, is capable of effectively replicating in macrophages, thereby leading to macrophage activation and a polysystemic inflammatory state and immune dysregulation [1,5]. Affected cats develop a variety of clinical signs, such as anorexia, lethargy, weight loss, pyrexia, ocular and neurological signs Aim of this study was to evaluate the diagnostic value of detecting feline coronavirus (FCoV) RNA and spike (S) gene mutations in cerebrospinal fluid (CSF). Larger populations of cats with neurological FIP should be explored in future studies

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