FIV positive kitten

Re: FIV positive kitten

Suzanne Kelly — Sat, 31 Aug 2013 23:27:09 GMT

If it is genuinely +ve the CP in bredhurst may take it, they have a special FIV unit.

Re: FIV positive kitten

Joyce Whitehead — Sat, 31 Aug 2013 15:06:45 GMT

We had an FIV positive queen with 4 week old kittens. She came in via CPL for spaying as a feral, and was positive on snap test (and had various non healing wounds so was likely starting with illness). On their request she was euthanised and the kittens reared. We did PCR on those via Langford and surprisingly all were negative. Then someone at CPL decided to snap test the kittens again before rehoming, and of course they were positive due to the queen's antibodies. After advice, PCR was repeated and was again negative, as it should be as it was the first time! All are rehomed and hopefully all still healthy. So I think if they are tested by PCR you can be confident they are fine.

Re: FIV positive kitten

Christopher Saul — Sat, 31 Aug 2013 15:02:23 GMT

I would definitely do a confirmatory test, preferably a PCR.

as well as the issue of maternally derrived antibody, theres also the crucial question of statistics.

What we really are interested in is the positive predictive value of this test, not so much the specificity.

What we all sometimes forget is that the PPV of a test is influenced by the disease prevalence as well as the speccificity of the test; the PPV of a test breaks down a bit when the prevalence of the disease is very low.

I don't have the true figures to hand so as an example let's say that a test for a disease has a 99% specificity. This means that for every 100 individuals we test we will get 1 false positive. Now lets assume we have a disease with a very low prevalence, say 1%. so out of our 100 individuals, we get 1 actual true positive. 2 positives in total, so there is a 50% chance that the test is wrong and it's a false positive!

The reason I think this is relavent in this case is that we are testing a cat which seems healthy. In a population of HEALTHY cats, the prevalence of FIV will be low, much lower than a population of cats where you might have reason to suspect FIV

There's nothing wrong with screening healthy cats for FIV, but as they are clinically healthy there will almost by definition be a low disease prevalence in that population ( i.e. healthy cats), you should really have a healthy skepticism for a positive result and do a confirmatory test

I'm sorry foe being a boring arse. I'll climb down of my soapbox now.

Chris

Re: FIV positive kitten

Rob Loxley — Sat, 31 Aug 2013 11:26:45 GMT

and http://www.cats.org.uk/uploads/documents/Info_for_Vets/FIV_FeLV_flow_charts.pdf which for kittens <6mo suggests confirmatory PCR rather than IFA given the potential for persistence of maternal antibodies beyond 16 weeks

Re: FIV positive kitten

Cat Henstridge — Sat, 31 Aug 2013 10:58:31 GMT

Hi,

Thanks for the pricing info John, it wasn't as much as I thought! I might see if they will do that at 16 weeks + so we can be doubly sure of the correct result.

I know FIV+ve cats can live with negative ones but I am not sure with 11 others in the house it would be that suitable (quite apart from having that number of cats anyway!). The chap works with the local CPL, hence the knowledge and, probably, the numerous cats, so we might find somewhere that will take it but he thinks the local branch euthanase all the FIV +ve cats they get. Which is why I wanted extra information to try and get her a stay of execution!

Re: FIV positive kitten

Rob Loxley — Sat, 31 Aug 2013 00:00:12 GMT

[quote user="Francisco Gomez"]They used to work with IDEXX snap test and they seemed quite reliable. Now, (I guess due to costs), they started with Speed Duo (Virbac). This second test appears to be much more sensitive, hence getting some false positive results, later to be confirmed negative at external labs[/quote]

I've had the same experience, but I think it's more due to the speed-duo test being harder to read than the SNAP, and we went back to the IDEXX ones.
The ABCD guidelines are my go-to reference ATM

Re: FIV positive kitten

Suzanne Kelly — Fri, 30 Aug 2013 23:37:03 GMT

When I moved back home to Cork ( Ireland) I got an awful shock at the amount of FIV +ve cats here. I'd say at least 10% of cats are +ve if not more. Once I got over the shock, I realised most of them live perfectly normal lives and live to a ripe old age. My own cat is FIV +ve and has pemphigus and is perfectly happy and healthy. I have lots of clients where one cat is FIV +ve and their other cats are -ve. Does your client know the status of his other cats?

Re: FIV positive kitten

John Flynn — Fri, 30 Aug 2013 23:02:57 GMT

One more quick summary helpful link:

http://www.abcd-vets.org/fact_sheets/English/EN_FIV_Feline_immunodeficiency.pdf

Re: FIV positive kitten

Francisco Gomez — Fri, 30 Aug 2013 22:58:17 GMT

I've been working closely with Cats Protection in Nottinghamshire for a number of years. They used to work with IDEXX snap test and they seemed quite reliable. Now, (I guess due to costs), they started with Speed Duo (Virbac). This second test appears to be much more sensitive, hence getting some false positive results, later to be confirmed negative at external labs...

Re: FIV positive kitten

John Flynn — Fri, 30 Aug 2013 22:53:57 GMT

Great points, Cat.

Thanks for additional info about FIV antibodies from milk.

I guess you need to decide what to do with kitten until 16 weeks old then...

I'm not a big snap test fanatic (maybe they're better value if you use a lot).

Prices from: http://www.gla.ac.uk/media/media_196405_en.pdf

FIV antibodies is £18(+VAT) and that includes a western blot in addition to immunofluorescent testing in the event of the positive (I'd be a lot more confident on presence of antibodies given that increased rigour than just a SNAP test...)

Langford's price list isn't online - you need to request it.

Fingers crossed for the kitty

Re: FIV positive kitten

Cat Henstridge — Fri, 30 Aug 2013 22:14:41 GMT

Hi John,

Thanks for the link, I found this;

Queens pass antibodies to their kittens in their milk, especially in their first day of life, so that kittens of FIV positive queens can have positive FIV tests, although in fact they are not themselves infected - because of the antibody from their mothers milk. So it is essential that kittens of FIV positive queens are not FIV tested until they are at least 16 weeks old, by which time the antibody they got from suckling should have disappeared.

I was hoping this might be the case! Fingers crossed if I retest she will be negative. The virus isolation needs ml of blood, which is a lot for such a tiny baby and the cost may well be prohibitive.

Re: FIV positive kitten

Sammy82 — Fri, 30 Aug 2013 21:55:53 GMT

I would send blood to the lab, a snap test result (as any other diagnostic test) could be false positive.

Re: FIV positive kitten

John Flynn — Fri, 30 Aug 2013 21:49:23 GMT

Get some confirmatory testing done.

http://www.gla.ac.uk/schools/vet/cad/informationforowners/felineimmunodeficiencyvirusfiv/whydoihavetohavemycatsfivtestconfirmed/

I'd use Bristol or Glasgow labs.