Detection of XXXX spike gene mutations as a tool to diagnose feline infectious peritonitis.

@entity25443 @entity25444 @entity4334 @entity468 @entity204
OBJECTIVES: @entity25443 ( @entity25443 ) is an important cause of @entity204 in the cat population worldwide. The ante-mortem diagnosis of @entity25443 in clinical cases is still challenging. In @entity468 without effusion, a definitive diagnosis can only be achieved post mortem or with invasive methods. The aim of this study was to evaluate the use of a combined reverse transcriptase nested polymerase chain reaction (RT-nPCR) and sequencing approach in the diagnosis of @entity25443 , detecting mutations at two different @entity4334 positions within the spike (S) gene. METHODS: The study population consisted of 64 @entity468 with confirmed @entity25443 and 63 @entity468 in which @entity25443 was initially suspected due to similar clinical or laboratory signs, but that were definitively diagnosed with another disease. Serum/plasma and/or effusion samples of these @entity468 were examined for @entity25444 (FCoV) RNA by RT-nPCR and, if positive, PCR products were sequenced for @entity4334 transitions within the S gene. RESULTS: Specificity of RT-nPCR was 100% in all materials (95% confidence interval [CI] in serum/plasma 83.9-100.0; 95% CI in effusion 93.0-100.0). The specificity of the sequencing step could not be determined as none of the @entity468 of the control group tested positive for FCoV RNA. Sensitivity of the 'combined RT-nPCR and sequencing approach' was 6.5% (95% CI 0.8-21.4) in serum/plasma and 65.3% (95% CI 50.4-78.3) in effusion. CONCLUSIONS AND RELEVANCE: A positive result is highly indicative of the presence of @entity25443 , but as none of the control @entity468 tested positive by RT-nPCR, it was not possible to confirm that the FCoV mutant described can only be found in @entity468 with @entity25443 . Further studies are necessary to evaluate the usefulness of the sequencing step including FCoV-RNA-positive @entity468 with and without @entity25443 . A negative result cannot be used to exclude the disease, especially not when only serum/plasma samples are available.
