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

Tissue samples were collected into RNAlater (Life Technologies) within 2 h of death, as per manufacturers' instructions, and stored at −80 °C pending molecular analysis. Further samples were collected into 10% neutral-buffered formalin for histological examination and IHC. The tissues collected comprised primarily mesenteric lymph nodes, liver, kidney, spleen and omentum, while other tissues (e.g. intestine, brain, lungs, pericardium, pancreas or other lymph nodes) were included based on gross pathological findings or reported clinical signs. Body cavity fluid samples (e.g. ascitic fluid, pleural fluid, pericardial fluid, aqueous humour and CSF) were collected into plain or EDTA-anticoagulant blood tubes. Where immediate storage at −80 °C was not possible, fluid was combined with RNAlater (20% v/v) upon collection and moved to long-term storage at −80 °C within 24 h to 1 week. Faecal samples were stored immediately upon receipt at −80 °C until use.