Trial by export

TRIAL BY EXPORT

12 1 AlJtumn 2012 1ALPACA WORLD MAGAZINE

TRIAL BY EXPORT

L ast winter Tracey and I confirmed a

saleof four females and one young male to Jorgen Larsson ofNybo Alpacas in

Sweden We had export ed alpacas to Joumlrgen in the past so we were prepared for the thorough testing requirements for the next export that we

had plan ned for the spring March came and the alpacas were blood tested for Brucellosis and skin tested for bTB in accordance with European law We also carried out some additional testing on the alpacas including IBRJohnes Disease and BVD On a cool March morning our vet arrived and certified the export and shortly afterwards the lorry from John Parker International came and

the alpacas were transported to Sweden The alpacas travelled weil and arrived at

Joumlrgens farm in good health where they were unloaded and then put into quarantine The Swedish government require alpacas to remain in quarantine in Sweden for 100 days post importation where they were subjected to more testing

As the Swedish quarantine process moved on the alpacas were in perfeet health and seemed to be enjoying the spring weatherIn late May the Swedish authorities decided to begin serological testing all alpacas imported from the UK for bTB as Sweden claims to be bTB free The choice oftest they decided to use was the Chembio Brock Stat PAK Test which is a blood test that is designed for testing badgers for bTB by looking for antibodies to two antigens associated with a bTB infection The authorities began to roll out the testing regime and Jorgens alpacas were first on their list The vets ca me to Jorgens farm in the week beginning the 21st of May and took blood

from all 5 alpacas and then sent the blood back to the UKfor testing

On the 6th ofJune the samples reached the UK for testing and on the 8th ofJune we were told

that two alpacas had tested positive to bTB and that they would be destroyed immediately This obviously came as a huge shock to Tracey and I not to mention poorJoumlrgen in Sweden On the 12th ofJune the hvo alpacas were slaughtered and post mortem testing began

The press in Sweden in fact the majority of the Scandinavian press went public with the result with the main headline being bTB found in alpacas imported to Sweden

We immediately questioned the result as 2 alpacas out of5 alpacas having bTB did not fit the health and bio security profile ofour herd of alpacas in England Surely this wasnt right We

also questioned the accuracy of the Brock STAT Pak test as we knew it achieved a minimum of7 false positive results and recent research in the UK indicated a much higher false positive rate when this badger test was used on alpacas

Our farm in Dorset has very tight bio security measures that we set up to limit the disease routes entering our farm We pride ourselves on having one of the tightest bio secure alpaca farms in the world We installed a 100 badger proofelectric fence nearly 3 years earlier we operate a 9 month quarantine on all alpacas purchased and entering the herd and these alpacas are tested for a variety ofdiseases before entering the premises There are disinfection points for all visitors entering the farm and we have a 5 metre non contiguous double fence surrounding the property Our adult mortality rate was also extremely low less than 05 per year and all deaths have full post mortem examinations carried out and we have never had any confirmation or suspicion ofbTB in the past

Back in February this year our vet Alastair Hayton from Synergy Farm Health informed us ofa new ground breaking bTB serological blood test that had been developed by Enfer

The implications of having sent infected alpacas abroad would be devastating for us arid other UIZ based alpaca owners

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TRIAL BY EXPORT

Enfer laboratories Nass Ireland

Scientinc ofIreland with over fSmillion worth

ofprivate funding The Enferplex TB test was developed to accurately detect bTB in live animals and it has been renned for commercial use in cattle and camelids Enfer Scientinc are working with Scottish scientists from MV

Diagnostics in a joint venture to develop the test in alpacas and other species induding humans Before the Swedish situation came to light

Alastair had already suggested that Inca Alpaca

might like to become the irst alpaca herd in the world to have this test performed on every alpaca

on the farm with a view to identifying our bTB status

The events in Sweden forced us to take some immediate action to identify our herd s bTB

status Ifwe did have a problem we wanted to nnd out right away After some intense discussions and thought we decided to have our entire alpaca herd blood tested using the Enferplex Test with a view to proving to the Swedish authority that our herd was serologically dear ofbTB

The science behind the Enferplex Test and the extensive testing that they had already carrjed

Example of typical res ults for 4 Alpaca blood samples

2 3 4

out on over 120000 of cattle 1300 alpacas and many more species gave us the conidence that the

EnferplexTest would give lIS an accurate result with a very low percentage offalse positive results

The brief science of the Enferplex test is When an alpaca is infected with TB its

immune system tries to controi the infection by making cell mediated responses and antibody responses These are two separate arms of the

immune system and act in different ways to try and controi the TB infection The presenee of these responses can be used to diagnose the fact that the alpaca is infected with TB Cell mediated responses can be detected by the skin test and by the gamma interferon test These become positive early in the infection but wane as the disease gets more serious Antibody responses can be

measured by the Enferplex TB test which can become positive about 2-3 weeks aEter the animal

becomes infected and generally gets stronger as

time goes on TB can be a very difficult infection to diagnose

Unfortunately not all animals whether alpacas cattle or humans respond to TB by producing detectable skin gamma interferon and or

antibodyresponses at all stages of the infection Further the skln test is very inaccurate in alpac~s

and the gamma interferon test while being a good test for cell mediated responsesIS expensive takes a long time to per form and requires very specialised facilities and expertise

to make it work

The Enferplex TB test is hoth sensitive (it is good at detecting infected animals) and specdic

(it can be set to mini mise any false positives) It is easy to take the sample and get it to the lab in goo condition it is relativel inexpensive to perform it is robust and produces objective results and th test can produce a result within 3 hours in the lab

The Enferplex TB assa) is a multiplex assa

which dctects antihodies to seven separate

puriiied antigens from the TB organism The antigens are spotted separately onto plastic and then reacted with serum from the animal If the animal is infected with TB and has antihodies in its serum these stick to the antigen spots on the plastic These antibodies can the n be revealed with a stain which cause s the spots to glo If the animal lIoes not have TB antibodies in

its serum the spots will not glo The mount oflight produced by the spot is a measure of the amount ofantibody in the serum and is recordec

via a digital camera and computer Because

the antigens are in separate spots rather than being mixed together as in other antibody tests the response to each antigen can be measured separately This makes the test very sensitive an(

very specitic as the number of antigens is greate l

than in other tests and you can see exactly whicl

antigens are being responded to by the animal lhe problem wIth -r D l lhdl l 1I l1 v uud l dllllU )

only make responses to a few antigens at a time and you need to use a panel ofseven antigens to get the best results This is true in hmans too

4 1Amn Jnl1 l Al PAr A WDRLD MAGAZINE

TRIAL BY EXPORT

We pride ourselves on having one ofthe tightest bio secure alpaca farms in the world

Enferplex test procedure

1 Blood sample

2 Test plate

3 Test Reader

4 Results analysis

Sample number l on the extreme left is from an uninfected animal The other samples are from 3 infected animals and show how the different

spots vary in the amount ofglow This shows that different animals produce different amounts of antibody to the different antigens and emphasises why you need a large number ofantigens in the

assay and that you need to be able to analyse the response to each antigen separately (not all mixed together as in the Idexx and StatPak tests) to get maximum sensitivity and specificityBack on the farm we quickly made preparations to take

blood from the whole herd and on the morning of the 21st ofjune three vets and a number of handlers took the blood we needed and it was

couriered to lreland for testing The results shortly followed out of265 alpacas 263 alpacas tested completely negative for bTB and 2 alpacas were considered to showa very marginal positive reaction on three antigens The advice of MV Diagnostics and Enfer Scientific was

that these two animals were very likely to be negative as their antigen profiles we re nowhere near the pattern seen in true positives However given the vital importance of clearing any doubt following discussion with Defra

these animals we re sent for a full post mortem carrie d out by the government body AHVLA - Animal Health Veterinary Laboratories

Agency - to confirm that they showed no evidence of disease Both alpacas were found to be completely elear ofbTB and were deemed to have given false positive results in the Enferplex test This equated to a 075 false positive rate when using the Enferplex Test Meanwhile back in Sweden the authorities had carried out full

post mortem examinations on the two Stat Pak positive alpacas and these two alpacas were found to be completely elear ofbTB on visual assessment microbiology histopathology and finally by culture These results ca me as a huge relief for Tracey and I as weil as all the breeders that keep their alpacas on our farm The implications ofhaving sent infected alpacas abroad would be devastating for us and other UK based alpaca owners

We are now confident that the Stat Pak test results on the two alpacas that were slaughtered in Sweden were false positives

The fact that the Stat Pak test was not validated or licensed for use in alpacas did not stop the Swedish Authorities using it as a test that would undoubtedly change peoples lives and businesses forever Before any attempts of confirmation ofdisease had been made the authorities had noti6e d other Scandinuvian

veterinary offices that we were a bTB infected herd and consequently that all alpacas exported to Scandinavia from our farm may have the

disease and should be tracked down and checked immediately

After we received our herd negative result for bTB from Enfer Group we began to dig into the procedures that we re followed by the Authorities in Sweden We immediately made some startling discoveries as to a possible reason the alpacas probably gave a false positive result when tested using the Stat PAK test

Chembio (the manufacturers of the Stat Pak) issue the instructions for the handling ofblood to be tested for bTB as follows

Samples perform best when tested

immediately after collection Specimens should be immediately refrigerated at 2 to 8degC following collection and can be used up to 3 days If testing within 3 days is not possible the specimens should be frozen at -20degC or colder

until use Avoid repeated freezing and thawing The National Veterinary Institute ofSweden

were aske d if the test material (blood) from our alpacas was frozen when it was sent to England and they said no The Stat Pak test was carried out in England 8 days after the blood was taken in Sweden

We cannot conflrm that the mishandling of the blood was the result of the positive

results or whether it is possibly due to the inherent specificity of the Brock Stat Pak Testthe Brock and Camelid Stat Pak tests no longer appear on the Chembio website as products for sale) ) but it certaini) has raised some questions What is for certain is that

Tracey and I as weil as all ofour customers and investors have been through a huge amount ofpain and anguish as a result of the positive

results this test produced and the consequent actions of the Swedish authorities not to mention the heartache Joumlrgen and his family have had to go through in Sweden when they watched two of their prized alpacas being put to sleep We have now been fully compensated for the loss of the alpacas by the Swedish Government and they are currently retracting their previous state ments regarding the suspected disease prevalence in our herd

Through the use of the Enferplex Test we es[tbli~hed that our herd is j crolo~ic a lly chac of

bTB and our tough bio security measures will ensure that we remain extremely low risk for years to come

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