VERGE Vet Services, Inc​

Copyright 2016 VERGE Vet Services, Inc.


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CWD and The VERGE Procedure

CWD – Chronic Wasting Disease – is a fact for the Cervid Industry.

Intelligent people can – and do – disagree on the nature of CWD, but the fact remains ... CWD adversely and dramatically impacts the Cervid and Wildlife Industries every day, and absorbs resources from both Industry and Regulators.

VERGE Vet Services is a pioneer in developing real-world solutions for industry and regulators to use TODAY.

Starting with the revolutionary VERGE Procedure, VERGE veterinarians have developed a variety of solutions and answers, and have moved the discussions on CWD forward... working together and leading to help industry, regulators, and the scientific community develop and deploy solutions that provide a win-win-win solution for all stakeholders and the animals affected by this disease – solutions that can be used to solve today’s problems, TODAY.

VERGE Veterinarians and staff have assisted State and Federal agencies, and Cervid Industry Associations in developing workable approaches to detecting and managing CWD, and to responding rapidly, rationally, and realistically to CWD outbreaks when detected.

VERGE continues to provide these cutting edge solutions to our clients at affordable prices, working to make the solutions available to breeders at all levels of the industry – and working towards making CWD a manageable issue.

Chronic Wasting Disease (CWD) is generally described as a transmissible disease affecting deer and elk (Cervids) as well as moose in both wild and captive populations. CWD is often described as “a progressive, fatal, degenerative neurological disease ...” There is no known treatment or vaccine for CWD, but it is not considered a risk to humans, nor is it transmissible to humans. The disease is transmitted by abnormally folded proteins, called ‘prions’. Animals infected with CWD may not produce any visible signs of the disease for a number of years after they become infected. As the disease progresses animals with CWD show changes in behavior and appearance, but unfortunately, these signs are not specific to CWD and can occur with other diseases or malnutrition... there is currently no immunization nor cure for CWD...” (

Because of the nature of CWD, regulatory testing for the disease requires sampling of either the Obex (a part of the brain stem) or the Medial Retropharyngeal Lymph Node (MRPLN). The MRPLN tissue is especially useful, since it has a greater than 99.9% sensitivity for detection of CWD and is recognized as the first tissue of detection for CWD – making it the regulatory “Gold Standard” tissue.

Under existing legal and regulatory guidelines, testing for CWD therefore occurs using a post-mortem collection of tissues. Many times (especially in CWD “trace” investigations), this requires that an otherwise healthy animal be euthanized to allow for testing. No one – not the breeders nor the regulators – has been happy with this situation. There have been efforts for years to find an alternative to this “kill-to-test” requirement. “Live”, ante-mortem testing has been a goal, and has led to the development of both rectal and tonsil tissue sampling tests for use in surveillance for the disease.

These surveillance tests are especially useful in wild populations. In wild populations, determining the prevalence or even the mere presence of CWD doesn’t require a diagnostic, regulatory decisions that can result in the destruction of an entire herd – and impact a breeder and in many cases, an entire community. So, while these surveillance tests show promise, they still face many challenges before they can be used diagnostically for regulatory and medical decisions. Among the key factors are:

  • Tissue test sensitivity and Biopsy sensitivity
  • Sampling error
  • Correlation between true disease status and the tissue test results
  • The impact of genotype on the test results
  • Disease progression and detection times in those tissues.

Because of these factors, these tests (rectal and tonsil testing) must be used for a large sample size in a population, requiring a large number of animals to be tested to achieve an acceptable degree of confidence – and then only a confidence (not a certainty) that IF CWD was present, the test SHOULD have found it. These issues are just some of the problems that must be addressed and solved for both regulators and industry to make these surveillance tests viable for regulatory and diagnostic work, work that requires a high degree of certainty that the disease is found if it is present.

The obvious solution then would involve using the existing “Gold Standard” tissue and tests, but to do so ante-mortem – allowing an animal to be tested and remain alive. Unfortunately, these tissues have only been obtainable using post-mortem collections ... removing a part of animal’s brain stem is always fatal, and the MRPLN tissues have been seen as impossible to obtain ante-mortem.

That is until now...

The VERGE Procedure is the first and only live (ante-mortem) test for CWD that uses the GOLD STANDARD tissue – the Medial Retropharyngeal Lymph Node (MRPLN) – the ONLY TISSUE APPROVED for use by the USDA’s CWD Program Standards and by every State CWD monitoring and management program. The VERGE Procedure provides a sample of the MRPLN tissue via a fully visualized biopsy. The biopsy is taken in compliance with USDA and NVSL protocols, using minimally invasive surgical procedures. 

The entire procedure takes from 8 to 12 minutes, start to finish, with the actual biopsy taking less than 2 minutes. Because of the anesthetic protocols used, animals are fully recovered and returned to grazing within 15 minutes. VERGE has also developed handling and anesthetic protocols for use on bred does and other high risk animals, allowing the total time subject to anesthesia to be minimized, reducing risk significantly.

The VERGE Procedure has a less than 1% incidence of post-surgical complications (mainly seromas that resolve within 24 hours), and a negligible (less than 0.5%) mortality rate.

The VERGE Procedure is appropriate for use as early as 12 months post-exposure for CWD Trace Investigations, and can be used in all genotypes. This provides a regulatory and DIAGNOSTIC solution that is useable a full 2 years prior to the next best surveillance live test. The DIAGNOSTIC aspect of The VERGE Procedure is important to note. Using the MRPLN tissue provides the ability to DIAGNOSE INDIVIDUAL ANIMALS without the need to also test large portions of the herd. This is a characteristic unique to The VERGE Procedure. The VERGE procedure can also be used on a whole-herd basis, providing a 99.9% DIAGNOSTIC answer for each animal – rather than a surveillance answer calculated at a lower confidence rate.

VERGE developed this procedure to allow rapid deployment and use under existing legal and regulatory requirements. The VERGE Procedure provides a CWD test solution that complies with all current Federal and State laws and regulations. The biopsy sampling protocol was developed in cooperation with NVSL, and meets or exceeds all requirements for use in all current regulatory lab tests (IHC, ELISA, and western Blot).

The VERGE Procedure provides an alternative to euthanasia to test for CWD. No longer do regulators and industry face the “kill-to-test” requirement when dealing with CWD
The VERGE Procedure also provides a critical tool for CWD researchers, allowing the use of Gold Standard tissues as a benchmarking and evaluation tool in studies on this disease.

The VERGE Procedure is currently in final review for approval by the USDA for use in the USDA’s CWD Herd Certification Program, and for addition to the USDA CWD Program Standards. We anticipate that this approval will be forthcoming soon – making The VERGE Procedure the first approved “live” ante-mortem test for CWD, and the only truly diagnostic ante-mortem test.

CWD Prevention and Best Practices
VERGE Vet Services leads the way in developing and deploying innovative and easy to use Industry Best Practices for the prevention and containment of CWD in the Cervid Industry. 
As practicing Veterinarians, the Verge Vet Services staff understand the need for practical yet complete methods to prevent the spread of CWD – from both suspect trace herds, and in general in the industry.

For this reason, VERGE has developed CWD-Safe Breeding and Veterinary Medical Practices that we use on every visit. We also provide our clients with best practices advice and guidance, to help them minimize risk and enhance their own bio-security. Many of these best practices are already things that responsible breeders do, and that current regulatory requirements provide for. VERGE’s solutions provide the extra measure of protection and peace of mind.


The State of Texas has taken a leading position in working to implement “live” ante-mortem testing for White-Tailed Deer and the Cervid industry – and this includes the first SUCCESSFUL USE of THE VERGE PROCEDURE for clearing both individual animals and entire herds. The Texas Animal Health Commission (TAHC) and the Texas Parks and Wildlife Department (TPWD) share responsibility for management and control of the cervid populations in Texas. This includes both farmed Cervids and wild populations. 

In early 2016, TAHC and TPWD sponsored a “CWD Symposium”, bringing together the leading experts on this disease. VERGE’s Dr. Nathan Shotts was one of only 5 nationally recognized experts - and the only practicing Veterinarian – to be asked to speak at this symposium. As a result of this symposium, TAHC began using various live test options in CWD “trace” investigations. TPWD is also evaluating the use of live test options in the movement qualification status for Texas herds.

VERGE Vet Services provides testing in ALL THREE possible test modes for our clients in Texas. VERGE’s Cervid Veterinarians are the only providers of MRPLN Biopsy testing – The VERGE Procedure – which is used for herd and individual animal clearance as early as 12 months, literally months and years before other tests.

VERGE Vet Services has also pioneered advancements in the rectal and tonsil surveillance techniques, streamlining them for use in captive, farmed cervid situations, as well as developing protocols to deal with bred does and other high risk animals. 
VERGE Vet Services provides MRPLN, tonsil, and rectal testing of Cervids in accordance with TAHC test programs – the only providers in anywhere with that capability. VERGE Vet Services also provides epidemiology and risk assessment consulting for clients affected by CWD, or who want to know what their risks are. Because of our strong working relationships with regulatory agencies and our experience with these situations, VERGE can provide assistance that is otherwise unavailable to industry.

VERGE has cooperative agreements with additional Veterinarians in Texas – The VERGE Network - who have training to provide either rectal or tonsil test sampling. This allows VERGE Clients to avoid the extended delays and schedule issues associated with the limited test windows for these programs. When combined with our advanced cervid anesthetic and care protocols, this allows VERGE Clients to “test out” with far fewer concerns regarding losses or complications due to this testing.

Information on Chronic Wasting Disease (CWD) can often appear contradictory and colored by different agendas. We encourage our clients, regulators, legislators, media, and decision makers to access the best, most accurate and unbiased information on CWD possible. We urge anyone with questions regarding CWD – and especially with any questions about live, ante-mortem testing and The VERGE Procedure - to
contact VERGE Vet Services

The following are some additional links to resources for information regarding CWD.
USDA CWD information page
TAHC CWD Information page
TPWD CWD information page
TAHC/TPWD CWD Symposium (recorded session Dr Shotts presentation is at 2hours and 27 minutes into the recording; the Q&A session starts at 6hrs and 48 minutes)