actions in the renin-angiotensin-aldosterone system, which suggests a common phylogenetic origin between these molecules. Some advanced studies have shown a high homology between the Aminopeptidase N and the Angiotensin-converting enzyme. It is more than likely that the unknown FCoV serotype I receptor is also a member of this receptor family and acts with mannose binding lectins. Interactions between the viruses and sialic acid Sialic acid is a component of the complex sugar glycocalix, which is the mucus protecting the gastrointestinal and respiratory mucosa. It is an important facilitating fusion factor of any viruses to its host cell which has been very well studied for flu. Extensive data also shows that processes using sialic acid are directly involved in the interaction with the receptor's lectins. 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. Feline coronavirus infections are therefore sialic acid dependent. The Porcine epidemic diarrhea virus (PEDV) S protein is 45% identical to FCoV type I spike. An EM structure of it shows sialic acid binding sites. The PEDV receptor is also unknown. Effects of breast milk on kittens Kittens born from mothers carrying FECV are protected from infection by maternal antibodies prior to weaning. It therefore is recommended that the kittens be weaned early and segregated from their mother before they infect each other (at about 5 to 6 weeks). Kittens with no outside contamination and that are deprived of contact with their mother during their first 2 months of life (an important immunological period) may be protected. Antibodies It is widely accepted that passive protection is passed on to kittens by immunoglobulins nursery (antibodies) provided by colostrum and the mother's milk. However, several questions arise: If this protection is only supported by maternal antibodies, why are these antibodies not protecting the mother herself? If the kittens born to a mother's blood group B are removed from their mother for 24 hours (to avoid hemolytic disease of the newborn) and thus have no systemic passage of maternal antibodies, why is FCoV infection not more common in these kittens than others? Colostrum Other molecules from colostrum and cat milk, could also bear this coverage: lactoferrin, lactoperoxidase, lysozyme, rich proline polypeptide — PRP and alpha-lactalbumine. Lactoferrin has many properties that make it a very good candidate for this anti-coronavirus activity: For