Limitations of using feline coronavirus spike protein gene mutations to diagnose feline infectious peritonitis

Barker, Emily N.; Stranieri, Angelica; Helps, Chris R.; Porter, Emily L.; Davidson, Andrew D.; Day, Michael J.; Knowles, Toby; Kipar, Anja; Tasker, Séverine

Two previous studies on cerebrospinal fluid only evaluated samples collected from the cerebellomedullary cistern [29, 30] . One study evaluated the use of immunocytochemistry for the diagnosis of FIP; when all samples were combined there was a sensitivity of 81% and a specificity of 85% [30] . The other study evaluated the use of RT-qPCR for the diagnosis of FIP, where the sensitivity was 42%, but specificity was 100 percent [29] . The results of the latter study are comparable with those of the current study (sensitivity 50%; specificity 100%). However, the apparent effect of the site of cerebrospinal fluid collection on diagnostic sensitivity of FCoV infection warrants further investigation. In cats with FIP there may be concern that some clinical signs could relate to increased intracranial pressure, where lumbar sampling could provide lower risk of herniation cf. cisternal sampling; however, FIP lesions rarely go beyond the leptomeninges of the brain stem (unpublished results).