Testing

[tat111]

Hi,

I am a little confused about testing procedures. I read samples can be sent overseas for PCR tests. Our avian vet suggests this test is unreliable and suggests that tests take three weeks and cost about $160.

I have read of feather testing, DNA, and immulogical response. Is this the test the one that our vet is most likely speaking about.

DNA testing is strongly advocated in the USA as a reliable test. The only problem with it is that it gives no information about the bird's immune system. A bird that tests positive may well have the disease but it could also be a case where the virus is just passing through', as the bird's immune system is eliminating it (see Scenario 1 above). So birds that appear normal, but test positive will need to be re-tested in 90 days. Another concern is the negative result. Is the bird really free of the virus, or is it a carrier with the virus only intermittently appearing in its blood? Do you know the answer? I certainly don't just from a DNA test!

 

Another test that has been developed by Garry Cross and Shane Raidal is the antibody test. This test looks for the antibodies the bird produces to fight disease. When interpreted alongside DNA results it gives a much clearer picture of the bird's status. A bird that is DNA negative and has high antibody levels is almost certainly immune and not infected. A bird that is positive on DNA and has low or no antibodies almost certainly has the disease. A bird that is negative on both tests has probably never been exposed to the disease, and as such is very susceptible to infection. This is a difficult test to perform unfortunately, bringing its cost up considerably higher than a DNA test. But if you have expensive or rare birds I would strongly recommend that you use this test on all new birds.

[sue]

Tests performed by the vet are DNA, 2 are done, both at the same time, one from feather the other from blood.
These tests are highly acurate. If the bird shows clinical signs and the tests come back positive then the bird is confirmed positive and no follow up test is required.
The follow up test at 90 days is if a positive result is received and the bird is not showing clinical signs, that is beak dystrophy, feather loss, malformation etc.
If the second test is positive then it is confirmed as having PBFD.

Hope this helps explain your above quotes. I am in contact with Shane, he is one of our leading PBFD scientists. All tests performed in Australia are of a higher accuracy than overseas.

You may like to join the cause on Facebook.  There is also a painting up for sale, all profit is to be donated to Shane Raidal.
http://apps.facebook.com/causes/294975/60514720?m=6d54c0aa

[tat111]

Thankyou for your reply. I should have asked my vet for more details at the time when he suggested more thorough testing was needed than a blood panel.

Do these tests look at the antibodies when testing the blood and feather or much like the test done when South African labs do tests on the blood (a PCR test AFAIK).

[sue]

I am not too sure on the testing that you are talking about in SA. 
The testing here is done on blood and a new feather.  It is far more acurate than blood alone.
The virus manifests itself in open orafices, the feather is a great place for it to get a hold, hence the need to test feather, it can be picked up there before it hits the blood supply.
This link may give you more info.  http://www.environment.gov.au/biodiversity/threatened/publications/tap/hygiene-protocols/chapter2.html
I have taken it from the main website, you may like to take a look at the website for more indepth info on the disease and testing procedures in Australia.

www.manauspbfdiseasesite.com

PBFD can remain in the bird for many years, including the liver, this is why I guess a positive result can also be achieved even though the bird is not showing any symptoms.

As far as my research goes, I have not found any evidence that once a bird in captivity has contracted PBFD it can shed the disease with a natural immunity, the exception are those in a Scientific Lab, undergoing vaccination studies.

Rainbow Lories in the wild are the exception.  http://www.birdhealth.com.au/bird/lorikeets/disease.html

[tat111]

Thanks again.

This explains why our avian vet sees little value in sending bloods from twenty odd birds OS as this screening process will not prove very much (we are in Australia).

It is a frightening disease, if we knew any better at the time we would have far fewer birds and had bloods and feathers done before they joined the flock. He told us to stop adding parrots which is what we have done. Or take a greater interest in non parrot species.

It is rather inspirational how you have cared for your Sulfurs.

Thanyou again.

[av]

Just adding to this.

The PCR test can be done by the Melbourne lab and after using both it and the South African lab I would use the Melbourne lab every time now as they are much quicker to come back.

My Eckkie is showing no signs of PBFD but has tested positive.  We are re testing mid Oct to see if she is building an immunity and will "shed" the diease and effectivly become immune. This is what my vet told me anyway.  Sue not meaning to sound like I am saying your wrong but just saying what my vet said.

I have also read about love birds who had PBFD and now don't so I am keeping my fingers cross that this is the case with willow as well

[sue]

No offence taken AV. Yes it is correct, some do survive, but it is not often. I cannot find scientific evidence for this though, Rainbow Lories are the only ones I can give the link for. All information and findings are important for the forum, thankyou for taking the time to post what you have done and been told by your vets, it will help others searching for info and give hope especially if second test results are negative.

Is there any chance that either of you could give a bit more info on the SA testing procedure, if you have any links to labs that you can place showing the procedure could you put them in, this would be much appreciated as OS testing is something I have not really researched on.

Kind regards
Sue

[tat111]

These are the folks I am thinking about.

http://www.mdsaustralia.net/site/prodcat.asp

From my reading they will do the test for less than $30 with blood taken from a toenail. A cocktail of tests testing for 4 different pathogens for less than $100. This is why I was more than a little surprised by the price getting tests done in Australia but I am assuming they are far more involved. Our vet was not interested in the labs I mentioned in the link and suggests the test would be  inaccurate.

What I am surprised about is that tests do not check antibodies to PBFD to rule out a false positive as seems to be indicated in my quote. From my understanding this is not the same test as the PCR test, more involved and more expensive.

[sue]

I just did some research and found this for both of you.  Hope this helps explain a little clearer than I can.
Cheers
Sue.

Before you read though, I have been searching our own forum and this has been here all the time.
http://manauspbfdiseasesite.com/forum/index.php/topic,50.msg130.html#msg130


Khalesi B, Bonne N, Stewart M, Sharp M, Raidal S.

Division of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA 6150, Australia.

Psittacine beak and feather disease (PBFD) is recognized as a threat for endangered psittacine birds in Australia, New Zealand and South Africa. Several diagnostic methods for the detection of beak and feather disease virus (BFDV) infection have been developed but there are few studies comparing the relative merits or sensitivity and specificity of each diagnostic test. In this report, the results of PCR, haemagglutination (HA) and haemagglutination inhibition (HI) testing of diagnostic samples collected from 679 samples from a range of psittacine bird species suspected of being infected with BFDV are summarized and compared. There was a strong agreement (kappa = 0.757; P<0.0001) between PCR and HA testing of feather samples and PCR-negative birds were 12.7 times more likely to have HI antibody than PCR-positive birds. False-positive HA results with titres up to 1:320 were identified in six feather samples that were PCR negative; the haemagglutination detected in these samples was not inhibited by anti-BFDV antisera and was removed by filtration through a 0.22 microm filter. Similarly, one false-negative PCR result was detected in a feather sample that had a high HA titre (>1:40,960) and four false-positive PCR results were detected in a batch of four feather samples. Of 143 birds that were feather PCR positive, only two had detectable HI antibody, and these birds were also feather HA negative, suggesting that they were developing immunity to recent infection. All birds with HI antibody were negative on feather HA testing. The assays confirmed BFDV infection in two endangered swift parrots (Lathamus discolor) and phylogenetic analysis of the sequence data generated from ORF V1 of these isolates provide further evidence of BFDV genotypes clustering in parallel with the Loriidae, Cacatuidae and Psittacidae.

PMID: 16227226 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/16227226?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=2&log$=relatedarticles&logdbfrom=pubmed

[sue]

Acute and chronic forms of PCD are recognised. In the acute form diarrhoea and feather abnormalities are symptoms, and death may occur suddenly within one to two weeks of developing clinical signs. The chronic form results in feather, beak and skin abnormalities, with most birds eventually dying. Complete or partial recovery from acute PCD has been recorded in some species (budgerigars, rainbow lorikeet, lovebird, king parrot and eclectus parrot), perhaps related to antibody in the blood. The majority of psittacine species with chronic PCD do not have antibody, do not recover and do not respond to treatment.

http://www.environment.gov.au/biodiversity/threatened/ktp/pcd.html