Isolation and Molecular Detection of Feline Infectious Peritonitis Virus

Abstract

Feline coronavirus (FCoV) is an enveloped single-stranded RNA virus, affecting wild and domestic cats. Feline infectious peritonitis viruses (FIPV) variants of FCoV cause fatal peritonitis affecting approximately 5% of FCoV infected animals. The present study aimed to detect and isolate the feline infectious peritonitis virus for the first time in Iraq. In this study, 50 samples (fecal swab and peritoneal fluid) were collected from suspected pet cats from different areas of Baghdad, Iraq. The very suitable age was under two years old. Real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) was used to detect Feline infectious peritonitis in infected collected samples by the amplification of spike protein (S). The result of real-time RT-PCR revealed that out of 50 samples from suspected cats, 10 samples were positive for FIPV. Moreover, 10 positive samples by real-time RT-PCR were used for the isolation of the virus in chicken embryo fibroblast cell culture. Subsequently, the isolated virus was detected by real-time RT-PCR and then by conventional RT-PCR, followed by electrophoresis.

Keywords: Cell culture; Feline coronavirus; Feline infectious peritonitis virus; Real-time RT-PCR.

Figure 1

Amplification of real-time polymerase chain reaction for the detection of infectious peritonitis viruses showed CT value of positive samples with amplification of s gene

Figure 2

Control, uninfected chicken embryo fibroblast monolayer (100x)

Figure 3

Cytopathic effect of feline infectious peritonitis on chicken embryo fibroblast cell culture (first passage), illustrating the rounding of infected cells and syncytia formation (100x)

Figure 4

Cytopathic effect of Feline infectious peritonitis virus on chick embryo fibroblasts cell culture, displaying the rounding of infected cells (passage second) and syncytia formation after 24 hours post-inoculation (100x)

Figure 5

Cytopathic effect of Feline infectious peritonitis on chick embryo fibroblasts (CEF) cell culture after 24 hours (passage three), demonstrating the rounding of infected cells and syncytia formation after 24 hours post-inoculation

Figure 6

Plot of amplification of real-time reverse transcription-polymerase chain reaction for the detection of isolated Feline infectious peritonitis virus on cell culture showed positive samples with amplification of S gene

Figure 7

Gel electrophoresis showing a 223 bp band after purification and amplification of gene

Figure 8

Electron microscope showed the morphology of feline infectious peritonitis virus crown-like appearance of isolated feline infectious peritonitis virus by using Electron Microscope