Thanks for the welcomes.
I got Taggart from a cat's home when was 2 or so - maybe a bit younger. My vet says that he most probably contracted AIDs through fighting. Apparently it is transferred through saliva when they bite each other.
Taggart has always been fond of defending his territory fiercely. I have another cat too, they are not very fond of each other and occassionally get into fights. I had her tested for the virus but thankfully she came back negative. Then I had to get her vaccinated of course. No wonder my vet drives a nice car!
Thanks for the feedback.