Hi Stefano,

Thanks for your question.

What a kind person you are caring for these kitties in need! The signs you described are definitely concerning. My first thought would be an upper respiratory tract infection (very common in cats, especially feral and outdoor cats), caused by one of several viruses. However, really it would be challenging to know without performing a thorough physical exam and assessment of the sick cat. There may be more than one problem going on here, especially as you mentioned, there may be some weight loss.

If she is at the point where she is having trouble breathing, then a supplement or diet change are unlikely to make a significant difference. She will likely need a prescription from a veterinarian at a minimum. With feral kitties, the challenge is safely catching them up to have them examined. If they are truly feral, then they may need to be trapped similar to a wild raccoon, as they will not tolerate handling. There are several organizations in Toronto and other large cities that are experienced in trapping and caring for feral cats. I would recommend contacting one of these in your area for advice.

In this situation, I would also recommend ensuring your own cat is fully vaccinated. Since feline respiratory illnesses are highly contagious, your cat is at risk as well. Vaccination can reduce this risk. Please also ensure you wash the bowls you feed the cats with thoroughly, as well as your hands after handling the bowls or the cats themselves. There are several serious illnesses common in outdoor and feral cats that are transmissible to other cats via saliva. I hope this provides you with a bit of clarity on this situation.

Best wishes,

Dr. Kim Hester