News

EQUINE ALLERGY

THE GROWING ACCEPTANCE OF TESTING AND SUBSEQUENT TREATMENTS

HORSE HIVES circleBoth allergen-specific immunotherapy (ASIT), and the use of environmental serological testing as an aid to the diagnosis of atopic dermatitis, are clinically well accepted within canine practice 1. This is not currently the situation for equine allergy cases, although ASIT in horses is becoming a much more accepted and frequently conducted treatment, with the benefits discussed at the World Congress of Veterinary Dermatology in Bordeaux last year 2,3.

Dr. Yu, who presented in Bordeaux, wrote in the proceedings of the American Association of Equine Practitioners convention 2015, these take home messages; 1) “Treatment of equine allergies requires a multi-modal approach including environmental control, topical, and systemic therapy, and allergen-specific immunotherapy”. 2) “Allergen-specific immunotherapy should be considered for all presentations of equine allergies including hives, heaves, scratches, and head-shaking as it is a cost-effective weight independent treatment option that is not banned by the FEI, has minimal adverse effects, and may eventuate a cure”.4

To enable ASIT, and also allow targeted avoidance, problem allergens first need to be identified. Much of the recent literature states that either serological testing or intra-dermal skin testing are acceptable methods for equine allergen detection in atopic dermatitis, respiratory allergies and insect bite hypersensitivity (IBH).2,5,6,7

Similarly to canine allergy diagnosis, judicious interpretation of either test result is critical as Marsella (2013) states; “the single most important aspect in formulating a successful immunotherapy is not which test is used but how the allergens are selected (i.e., emphasis is placed on correlating the results with the seasonality and environmental exposure of the individual patient to increase the likelihood of including clinically relevant allergens among the ones that tested positive”)8. With the recent advent of more relevant allergens available through our serological test (UK and Northern European panel), it is hoped more horses will now benefit from ASIT.

Request your FREE Equine Lunch and Learn here.

(1) Olivry, T., DeBoer, D.J., Favrot, C., Jackson, H.A., Mueller, R.S., Nuttall, T & Prélaud, P. (2015). Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee
on Allergic Diseases of Animals (ICADA). BMC Veterinary Research, 11:210
(2) Mueller, R.S., Janda, J., Jensen-Jarolim, E., Rhyner, C. & Marti, E. (2016). Allergens in veterinary medicine. Allergy 71: 27-35
(3) Loewenstein, C. & Mueller, R.S. (2008). A review of allergen-specific immunotherapy in human and veterinary medicine. Veterinary Dermatology 20(2): 84(15)
(4) Yu, A.A. (2015). Treatment of Equine Allergies. In: Proceedings of the 61st American Association of Equine Practitioners convention, Las Vegas, 2015
(5) Fadok, V.A. (2013). Update on equine allergies. Vet Clin North Am Equine Pract. 29(3): 541-550
(6) Jensen-Jarolim, E., Einhorn, L., Herrmann, I., Thalhammer, J.G. & Panakova, L. (2015). Pollen allergies in humans and their dogs, cats and horses: differences and similarities. Clinical and
translational allergy 5:15
(7) Stepnik, C.T., Outerbridge, C.A., White, S.D and Kass, P.H. (2012). Equine atopic skin disease and response to allergen-specific immunotherapy: a retrospective study at the University of California
Davis (1991-2008). Veterinary Dermatology, 23(1):29-3
(8) Marsella, R. (2013). Equine allergy therapy: Update on the treatment of environmental, insect bite hypersensitivity, and food allergies. Vet Clin North Am Equine Pract. 29(3): 551-557

BSAVA Congress 2017

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Avacta Animal Health are delighted to be exhibiting at the BSAVA Congress in Birmingham from 6 – 9 April 2017. Come along to stand 808 to say ‘Hello’

Whether you want to know more about our allergy services or our non-allergy products and innovations such as our canine lymphoma multi-marker algorithm-based test, there will be someone available to answer your questions.

At our stand you have the chance to win a £100 Amazon gift card by completing the exhibition voucher in the delegate packs, and whilst you’re there you may like to show off your creative skills by entering our ‘Name the PAW Pets’ competition.

Finally, there will be the opportunity to register your interest and get an exclusive look at this year’s Pet Allergy Week pack!

We look forward to seeing you there!

REGISTER NOW – FOOD ALLERGY WEBINAR – FRIDAY 21ST APRIL, 1PM

FREE FOOD ALLERGY WEBINAR – GETTING THE BEST FROM DIET TRIALS.

Presented by Dr Tim Nuttall, BSc, BVSc, CertVS, Phd, CBiol, MRSB, MRCVS

DATE: Friday 21st April at 1pm

Equine AFR Cat AFR_ Resized 

This webinar will review the developed awareness of adverse food reactions and how these affect the skin. It seems that adverse food reactions are relatively common in atopic animals and probably underdiagnosed. Unfortunately, we’ve also learned that they are more complex than first thought; recognition, diagnosis and management of adverse food reactions can be challenging. This webinar will discuss the following:

  • Defining food allergy syndromes
  • Clinical features of adverse food reactions
  • Selecting appropriate foods using history, serology and other tests
  • How best to follow up diet trials
  • Hidden allergens in foods, novel foods and food cross-reaction
  • How hydrolysed does a food need to be?
  • The role of the gut microbiome and probiotics

We’ll present the latest evidence and do some myth-busting along the way!

This webinar is suitable for both vets and nurses that deal with food-allergic animals and their owners. To sign-up for the webinar, please click HERE

   Webinar Club logo

Avacta Animal Health 2016 Christmas opening hours

Please note over the festive period we will be closed for the national bank holidays. The customer services department and laboratory will be open for the normal working days between Christmas and New Year from 09.00 – 15.00.

All canine Lymphoma Blood Tests and Acute Phase Protein tests will be run as normal during working days.

Full working hours will resume on Tuesday 3rd January.

May we wish you a Happy Christmas and New Year from all the team at Avacta Animal Health.

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Visit us at London Vet Show 2016!

lvs-buttonWe are delighted to be exhibiting and supporting the London Vet Show holiday passport at this year’s event in its new home at ExCel. Come along to M63 to learn about our complete allergy service of tests and treatments, including our new enhanced equine allergy test.

We’ll also be showcasing our range of revolutionary multi-marker algorithm based tests, including the canine lymphoma blood test (cLBT), and you can enter our caption competition courtesy of Natural VetCare Prescribed and have your advert created in Vet Times and VN Times!

We look forward to seeing you there!

Presentation at this summer’s World Congress of Veterinary Dermatology by Avacta’s Senior Research and Development Scientist Jennifer Bexley

At this summer’s World Congress of Veterinary Dermatology (WCVD) in Bordeaux, Avacta Animal Health’s Senior Research & Development Scientist Jennifer Bexley, at her 3rd successive WCVD, presented her research on SEROLOGICAL CROSS-REACTIVITY BETWEEN BEEF, LAMB AND COWS’ MILK ALLERGENIC EXTRACTS IN DOGS, which was co-authored by TJ Nuttall, B Hammerberg and REW Halliwell (Veterinary Dermatology 2016, 27 (suppl) 7).

Here’s a summary from Professor Richard E W Halliwell and the implications this has on the selection of foods for the diagnosis and/or management of possible cases for adverse food reactions (AFR).

 

Summary: The immunopathogenesis of adverse food reactions (AFRs) in dogs is uncertain, but likely to involve both IgE and cellmediated hypersensitivity. Supporting this contention are previous studies which showed an excellent correlation between results of patch testing (which is indicative of cell-mediated hypersensitivity) and results of provocation challenges with the same antigen. Similarly, in the same study, there was a high negative predictive value of both IgE and IgG serology and results of provocation challenges – i.e. if serology was negative, then there is little likelihood of involvement of that particular food (Bethlehem, Bexley and Mueller, Vet Immunol Immunopathol, 2012, 145:582-589). These studies have emphasised the need for knowledge concerning cross-reactivity of food antigens recognized by canine patients, so that potentially cross-reacting antigens can be avoided in the selection of antigens for inclusion in hypoallergenic diet trials.

The research reported herein was conducted by scientists at Avacta Animal Health and presented at the 8th World Congress of Veterinary Dermatology in Bordeaux this June. As a first step, results of serology for food antigen-specific IgE in sera from 469 dogs with suspected AFRs were analysed for evidence of statistically significant associations between multiple positive reactions within and across related antigen groups, i.e. mammalian, avian, fish and plants. It was found that there was a far greater likelihood of multiple positive reactions occurring to antigens within the same group, rather than between antigens in unrelated groups. Reactions to beef, lamb and cows’ milk were the most strongly correlated. However, this could be the result of co-sensitisation rather than cross-reactivity. Therefore in the second phase of the study, sera that were reactive to at least two of the three antigens (beef, lamb and milk) were selected for performing ELISA inhibition studies. In these, the addition of (say) beef antigen to a serum reactive to lamb (or milk) was assessed for the ability to inhibit the reaction, thus confirming true antigenic cross-reactivity. It was found that beef and lamb were highly cross-reactive, with milk also being cross-reactive although slightly less so.

Comments: These findings have important implications for the selection of foods for the diagnosis and/or management of possible cases of AFR. Thus if dietary history indicates that beef has been fed, lamb and dairy products should also be avoided in the selection of the most appropriate hypoallergenic diet trial. Similarly, if the history specifically implicates one of these antigens, all three should be avoided.Although antigenic cross-reactivity was only proven in respect of these three antigens, the fact that positive reactions in multireactive sera were significantly associated within rather than across related antigen groups suggests that further studies will likely show additional cross-reactions within antigen groups. In the light of this it would be prudent to formulate diets that avoid all antigens within the relevant group. So if a mammalian food has been fed, the trial diet should come from the avian, fish or plant group and vice versa. Of course, if serology is undertaken, then the existence of any possible cross-reactivity in the individual patient will become evident, and dietary selection can be optimised by choosing antigens with no serological reactivity.

To rule in or rule out – that is the question…

By Mark Dunning, MA VetMB CertSAM PhD DipECVIM-CA MRCVS, Clinical Associate Professor in Small Animal Internal Medicine, School of Veterinary Medicine and Science at the University of Nottingham.

Sensitivity and specificity remain the statistical measures by which veterinary surgeons select their tests in an attempt to reach a confident diagnosis. These values are (usually) determined from ‘pure’ populations of animals with and without a particular disease using the gold standard reference test. In the ideal world sensitivity and specificity would both be 100%. This would mean that the test was perfect at both ruling out (excluding) and ruling in (diagnosing) a particular disease. Whilst this is desirable, in reality this is almost impossible to achieve. In reality what is achieved is a compromise between each measure. We will return to this concept in a future article.

Sensitivity represents the true positive rate – i.e. the number of animals correctly identified with the condition. Specificity represents the true negative rate – i.e. the number of animals correctly identified as not having the condition. Whilst applying sensitivity and specificity measures, we must remember that these have (usually) been determined in a pure population of affected and unaffected animals. This aspect must be considered in order to understand how these tests perform in particular clinical settings where the population is poorly defined……

Clearly when trying to diagnose a particular disease, we do not know whether it is present or absent, hence the reason for the test (!). Test performance becomes heavily influenced by the individual case and setting. The strengths of each measure must therefore be considered when attempting to interpret the test. So, to consider the terms slightly differently:

    • sensitive tests are best at ruling disease out (SeNsitivity OUT – SNOUT)
    • specific tests are best at ruling disease in (SPecificity IN – SPIN).

Therefore, if we want to use each test to the best of its capability we must refine our clinical approach and choose whether we want to exclude or diagnose the condition. This may seem obvious, however in many clinical situations vets are looking to diagnose a particular condition when they may be better excluding it. This is particularly true when seeing a case for the first time, as many different diseases are often being considered at this point. Unless a multitude of clinical signs are present at the time of first presentation (raising a very strong suspicion for one particular disease), a rule-out approach has the greatest strength.

It is therefore important to refine the clinical question that needs answering in order that the test result is reliable. In order to get the best out of the tests you are using it is desirable to know whether you should be trying to rule out a particular disease or rule it in. So using the little aide mémoires of SNOUT and SPIN, let’s use hyperadrenocorticism as an example:

If we consider dog 1 that is only suffering with PU/PD we would want to exclude it from our list of differentials as the likelihood of this being the cause is reasonably low when only one clinical sign is present.

If we consider dog 2 presenting with PU/PD, polyphagia, a pot-belly, lethargy and alopecia we would be highly suspicious of hyperadrenocorticism and therefore we would look to diagnose the disease not rule it out.

Under these situations, a sensitive test would be most appropriate for dog 1 whilst a specific test would be most suitable for dog 2 (SNOUT and SPIN).

We hope this helps with some aspects of your clinical decision-making and in selecting the most appropriate test for your case. This will help to avoid errors in result interpretation and ultimately misdiagnosis. We will follow this up in the next newsletter and discuss the importance of predictive values which are an essentially ‘applied’ sensitivity and specificity.

New case study – Tizer the horse

Tizer well 3Tizer, an ex-race horse, had erupted in severe hives. A long-acting steroid gave relief, but once it had worn off the hives returned. As part of an elimination process for finding out what was causing the hives, a SENSITEST allergy test was conducted.

Click HERE to read the full story and how SENSITEST helped Tizer                                       become hive free.

Case study – LOL the cat

montage_LOLRead how LOL, an 8 month old European short haired kitten who was being treated for generalised pruritus with severe lesions, benefited from a Feli-DIAL® test. This unique test assists in the selection of veterinary prescribed diet for an elimination dietary trial, as it detects the presence of specific IgE for each of the allergenic proteins contained various veterinary prescribed diets alongside the animal’s existing diet. To read more on LOL’s story click HERE

PAW Competition Winner 2016

We are delighted to announce the winner of our 2016 Pet Allergy Week (PAW) waiting room display competition.

CONGRATULATIONS to the team at Companion Care Ely, who put together this eye catching display for their surgery, which was used to raise awareness of allergies in dogs and cats during last month’s Pet Allergy Week.

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Nancy, with her PAW waiting room display.

 

 

The display, which was used to inform clients about the signs and symptoms of pet allergies and the different allergens that can affect your pets, attracted a good amount of attention during Pet Allergy Week and the team were able to take advantage of the discounted tests that were offered out as part of PAW.

 

 

 

 

 

Nancy and the team and Companion Care Ely were delighted with their Lottie Shaw luxury Yorkshire hamper, as was the practice cat Brian.

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Nancy and Brian receiving the hamper

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Practice cat Brian was also pleased with the winnings.

 

 

 

 

 

 

 

 

 

 

 

Thank you to all the practices who entered our competition and took part in PAW!