DH's father just rung to say that one of our cats has cat flu but doesn't know much more than that (my SIL is house/cat sitting for us whilst we live out in USA for 6 months). The cat has been to the vet and had an injection and eye drops for associated conjuntivitis.. Does anyone know what this is like? Is it serious? Aren't they supposed to be covered against this in their annual vaccinations?