Feline infectious peritonitis (FIP) is a very difficult disease to deal with as it's hard to diagnose and treat.
(Q) I have two cats (mother and daughter) who have just been diagnosed with feline infectious peritonitis (FIP). They have presented with dry FIP, not the wet form and both have renal failure. We have two other cats and I have been told it is likely that they will all have the disease. But I'd like to know how my cats contracted FIP? They are all indoor cats, full vaccinated and only two have shown any symtoms.
Joe Inglis says: FIP is a very difficult disease to deal with as it is both hard to diagnose and almost impossible to treat.
The disease is caused by a virus which is very common and affects most cats to some degree or other. The reason why some cats develop the symptoms of FIP and others don't is down to their immune systems - ironically those cats that respond most strongly to the virus are those who suffer from the disease as the disease itself is caused by an overreaction of the immune system to the virus rather than the virus itself.
This means that only certain cats are likely to be at risk of this disease, and also that particular families of cats are more likely to be affected due to similarities in their genetic makeup and therefore their immune responses.
This is almost certainly why your mother and daughter cats have both been affected whereas the other cats in the household have shown no signs.
The virus that causes FIP is very common and is something that your cats could have been exposed to at any point, despite being indoor cats. Due to the near-impossibility of accurately confirming a diagnosis of FIP before a post mortem examination, you do need to be aware that it is not a 100 per cent certainty that this is what is affecting your cats and it could be that their renal problems are down to another disease process such as an inherited kidney problem for example.
Personally I don't think there is a great deal of point in keeping your other cats separate due to the fact that if this is FIP they have almost certainly already been exposed and not reacted badly to the virus, or it could be that this is not FIP but a genetic problem and therefore of no risk to your other cats.