ok, so it may be hard to definitively prove that a negative cat, after being vaccinated, became positive. But it can't be proved they haven't, either, so if someone wants to be safe and not mix I would not discourage that. I don't criticize anyone for mixing who does, but I also don't think anyone should be trying to convince someone who is hesitant that there is no way the negative can turn positive from exposure. You just don't know that, and there are some cases that indicate, potentially if not definitively, that they can. Michelle In a message dated 12/26/2006 2:46:08 P.M. Eastern Standard Time, [EMAIL PROTECTED] writes:
ah, but the issue is, "truly negative"--not only are snap tests not that reliable even when done correctly (which isn't always the case at shelters), but unless one knows for sure that any given cat couldn't possibly have been in contact with a positive cat for at least 90 days before a test, you can't really know that a negative test is accurate anyway. that's why retesting is so vital. shelters around here, until recently, only used the old-style saliva tests, which are incredibly unreliable--we brought an absolute sweetheart of a tortie into the house from there, and tho she'd tested negative (and had 4 supposedly healthy kittens, and nursed another 4 orphans), she ended up being diagnosed positive when she became very ill at about 18 months, and went to the bridge soon afterwards. in the household with her had been two kittens who'd only been about 3-months-old when they joined the household, as well as a couple of quite elderly cats--both high-risk populations, and none of the others in the household ever tested positive, luckily! (the 3-month-olds are now going on seven....) the need for retesting was just not clearly enough understood, nor was the great variability in accuracy in snap tests (i think susan h found research showing a range of errors from 20-80%!). i know of two sanctuaries that never retested their "positives," who have since begun doing so, and have discovered that a fair number of their older cats who have lived exclusively with FeLVs, often those with active disease, and who have had their own bouts of serious illnesses thought to be FeLV-related, who actually were found to be negative on the IFA, even after years of constant exposure....
