Sounds like what my vet calls "cat cold". It is caused by a virus (a strain of herpes but humans can't catch it) and it is incurable. If it is, they will carry the disease their entire life but can live normal, healthy lives with possible occasional outbreaks. We have had a few strays over the years with this. Anyway, if that is what it is, you are just going to have to treat the sytmptoms as they happen. My mother has a stray she feeds who is blind in one eye due to this. Good luck with them.
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