Feline coronavirus (FCoV) is a positive-stranded RNA virus that infects cats worldwide.

The only known exceptions are on the Falkland Islands and the Galapagos, where studies found no occurrences of FCoV antibodies in cats tested.

[5][6] Feline enteric coronavirus is responsible for an infection of the mature gastrointestinal epithelial cells[7] (see also enterocytes, brush border, microvilli, villi).

[7] Cats living in groups can infect each other with different strains of the virus during visits to a communal litter tray.

FIP has been shown to develop in cats whose immunity is low; such as younger kittens, old cats, immunosuppression due to viral—FIV (feline immunodeficiency virus) and/or FeLV (feline leukemia virus) and stress, including the stress of separation and adoption.

[7] Infection of macrophages by FIPV is responsible for development of a fatal granulomatous vasculitis, or FIP (see granuloma).

During the viral replication cycle, spikes proteins mature in the host cell Golgi complex with a high mannose glycosylation.

Coronaviruses bind to macrophages via the Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin (DC-SIGN) which is a trans-membrane protein encoded in humans by the CD209 gene.

[19] Aminopeptidase N has the same ability to interact with plant lectins C-type mannose-binding and also serves as a receptor for a retrovirus.

[20] Sialic acid is a component of the complex sugar glycocalix, which is the mucus protecting the gastrointestinal and respiratory mucosa.

Extensive data also shows that processes using sialic acid are directly involved in the interaction with the receptor's lectins.

[21] It has also been demonstrated that swine enteric coronavirus (group 1) fusion to the enterocyte is accomplished via binding to the APN in the presence of the sialic acid.

[24][25] The Porcine epidemic diarrhea virus (PEDV) S protein is 45% identical to FCoV type I spike.

[26] Other molecules from colostrum and cat milk, could also bear this coverage: lactoferrin, lactoperoxidase, lysozyme, rich proline polypeptide — PRP and alpha-lactalbumine.