A summary of UK Dachshund Breed Council IVDD research - January 2015
Post date: Jan 27, 2015 8:38:20 AM
For our latest advice and policy on IVDD and screening, please visit www.dachshund-ivdd.uk.
IVDD is the Number One health priority for the UK Dachshund Breed Council. All our health survey data confirms it is the most prevalent and serious condition affecting Dachshunds. Interestingly, our 2012 Breed Health Survey highlighted statistically significant differences in prevalence between the six varieties of Dachshund, with Smooths and Mini Smooths most at risk and Wires and Longs at lowest risk. This mirrors, to some extent, the findings of the Mogensen study in 2011 [Journal of Heredity 2011:102(S1):S81–S86] which found Smooth-coated dogs most at risk and Long-coated dogs, least at risk.
Our current research has three main strands:
Further investigation of the genetic basis for IVDD
Evaluation of alternative screening techniques
Identification of “Lifestyle factors” that may predispose Dachshunds to herniations
Additionally, we have been supporting research projects carried out at UK Veterinary Schools.
Genetic basis for IVDD:
This project, which is being carried out by the Animal Health Trust, aims to build on the 2011 work of Mogensen et al. That study used dogs with calcifications (cases) and dogs without calcifications (controls) and concluded that a major locus on chromosome 12 harbours genetic variations affecting the development of intervertebral disc calcification in Dachshunds.
Our project is using dogs that have suffered herniations in the lumbar region between the ages of 4 and 7 (cases) and dogs over the age of 12 that have never suffered back problems. This is a significant difference from the Mogensen study, which looked at calcifications, not herniations. Given that other studies have linked calcifications with risk of herniation, it will be interesting to see whether our project produces similar findings related to Chromosome 12..
We collected DNA swabs from 50 controls and 50 cases and the first part of the project started in the Summer of 2014. Here, the Animal Health Trust is looking at Chromosome 12 to see if they can find similar differences to that found by Mogensen. We are currently waiting to hear the outcome of this initial investigation.
It is highly unlikely that this research will lead to a “simple” genetic DNA test for IVDD because we know that environmental and lifestyle factors also play a part, but we hope it may lead us to some form of test that could give an indication of risk and help inform breeding decisions.
Alternative screening techniques
An interesting article on the use of Thermal Imaging to investigate Back Disease was recently published online by The American College of Veterinary Surgeons and in their journal Volume 43, Issue 7, , October 2014. We will be discussing this paper with the Royal Veterinary College to identify how we might use this information to build on our earlier pilot Thermal Imaging project. Here's the Abstract:ObjectiveTo: (1) determine the success of medical infrared imaging (MII) in identifying dogs with TLIVDD, (2) compare MII localization with magnetic resonance imaging (MRI) results and surgical findings, and (3) determine if the MII pattern returns to that of normal dogs 10 weeks after decompression surgery.
Study Design
Prospective case series.
Animals
Chondrodystrophic dogs (n = 58) with Type I TLIVDD and 14 chondrodystrophic dogs with no evidence of TLIVDD.
Methods
Complete neurologic examination, MII, and MRI studies were performed on all dogs. Dogs with type I TLIVDD had decompressive surgery and follow-up MII was performed at 10 weeks. Pattern analysis software was used to differentiate between clinical and control dogs, and statistical analysis using anatomic regions of interest on the dorsal views were used to determine lesion location. Recheck MII results were compared with control and pre-surgical images.
Results
Computer recognition pattern analysis was 90% successful in differentiating normal dogs from dogs affected by TLIVDD and 97% successful in identifying the abnormal intervertebral disc space in dogs with TLIVDD. Statistical comparisons of the ROI mean temperature were unable to determine the location of the disc herniation. Recheck MII patterns did not normalize and more closely resembled the clinical group.
Conclusions
MII was 90% successful differentiating between normal dogs and 97% successful in identifying the abnormal intervertebral disc space in dogs with TLIVDD. Abnormal intervertebral disc space localization using ROI mean temperature analysis was not successful. MII patterns 10 weeks after surgery do not normalize.
We are also following the development of various X-Ray screening programmes which have been implemented by various Dachshund Clubs in the US, Scandinavia and elsewhere. All of these are based on research published in numerous papers that show the risk of IVDD is correlated with the number of calcifications identified by X-Ray in dogs around the age of 24 months.
Over the past 12-18 months there has been much debate, particularly in Denmark, about the impact of this form of screening. The key question, which appears not to have been answered (at least in a peer-reviewed paper), is “has the screening programme reduced the prevalence of clinical cases of IVDD?”.
The advice we were given by geneticists and veterinary specialists from our Kennel Club in 2010 was that the case is not sufficiently proven to warrant implementing a similar, formal, X-Ray scheme in the UK. We will, of course, continue to review that decision as further evidence becomes available and have initiated discussions with Dr. Clare Rusbridge and Prof. Mike Herrtage to consider approaches that might be appropriate in the UK.
[For our latest advice (2016) and policy on IVDD and screening, please visit www.dachshund-ivdd.uk.]
Lifestyle factors
In 2013, Packer et al (from the Royal Veterinary College) published a paper demonstrating a link between the length:height proportions of Dachshunds and their risk of suffering from IVDD (this study looked at disk extrusions, not calcifications). The conclusion was that longer-bodied and shorter-legged Dachshunds were more at risk than those of more moderate proportions.This research has informed and reinforced our education programme for breeders and judges to select for more moderate conformation.However, the study also identified body condition as a significant risk factor; namely dogs that were over-weight or obese were also more likely to suffer disk extrusions. We are therefore currently conducting a Lifestyle Survey of Dachshunds which will be reported in 2015. This asks owners about how they rear, feed and exercise their dog(s), as well as reporting on any back disease. This survey has been developed with the support of the Royal Veterinary College. We hope to be able to use the results to produce improved guidance for owners on how to minimise the IVDD risks through lifestyle factors that they can influence.Other studiesDuring 2014 there were two other research programmes that we supported. The University of Surrey carried out a 'gait study' to examine the way healthy Dachshunds move. We helped recruit a group of Dachshunds and they plan to use the data to compare with dogs recovering from IVDD surgery.
We also helped recruit dogs for a gait study carried out by the Royal Veterinary College. This study looked at how fit, healthy Dachshunds with no neurological or orthopaedic problems move over a series of natural obstacles they encounter in day to day life, and on a treadmill.
