Dear Dr. Hines,

FCoV virus is responsible for a gastrointestinal epithelial cells infection with few signs, and it is usually chronic. FCoV is excreted in animal's feces (healthy carrier), and can be detected by PCR in feces or rectal swab. I has been shown that fecal samples that were negative to traditional PCR had few copies of RNA tested by real-time PCR. Properly design assay for FCoV can detect from less then 10 to 10^8 copies of viral RNA. Extraction methods for total RNA from various sample types (soil, fecal matter, collagen rich tissues, plants, microorganisms, etc.) in the past decade improved significantly, as well as the detection sensitivity of real-time PCR. So there is doubt in my mind, and that was based on our experience, that low presence of FCoV in intestines of cats can be detected by real-time PCR.
Best regards,