Netherlands Study on the prevalence of Chiari-like malformation and Syringomyelia

UK breeders may find this paper interesting. The Project Tutor is Dr Paul Mandigers, who gave a talk at the Cavalier Club AGM in 2013.

http://dspace.library.uu.nl/bitstre...n CKCS in NL between 2004-2012.pdf?sequence=2

Prevalence of Chiari-like malformation and Syringomyelia in Cavalier King Charles Spaniels in the Netherlands between 2004 and 2012

Some excerpts are shown below.........

"Only one dog out of 732 CKCS had no chiari-like malformation, nor did it show syringomyelia. It is possible that the dog developed it over time, it was only 1,2 years old at the time of the scan. All other 731 dogs had chiari-like malformation, indicating the severe impact of the disorder for this breed. In this study, approximately 37,6% of the dogs with CM developed SM. Since SM is a progressive disease in CKCS, it is possible that certain dogs with only CM may develop SM in the future. CM/SM has been shown to be inherited in the Cavalier King Charles Spaniel, although the mechanism of inheritance is not yet understood.

The dogs were divided into 3 age groups. There was a visible development that the prevalence of syringomyelia increased with age.

There is evidence from this data to suggest that the lifetime risk of developing SM may be even higher, because in CKCS of five years and older the prevalence was 58,7%

ConclusionChiari-like malformation and syringomyelia are a serious problem in the Cavalier King Charles Spaniel. There is a correlation between the prevalence and age of the dogs."

And another interesting Danish Study

http://onlinelibrary.wiley.com/doi/10.1111/jvim.12475/abstract

Results
The cross-sectional study estimated a prevalence of symptomatic SM at 15.4% in the population. Thirteen symptomatic and 9 asymptomatic siblings participated in the litter study. Spinal cord syringes were confirmed in 21 of 22 littermates (95%). Syrinx diameter and mean syrinx : spinal cord ratio were significantly correlated with clinical signs (P < .01). Estimated heritability of symptomatic SM was 0.81. Symptomatic SM motivated euthanasia in 20%. Dogs with syringes, which expressed no clinical signs at the age of 6, remained asymptomatic in 14/15 cases (93%).


Conclusions and Clinical Importance


The prevalence of symptomatic SM is high and genetics have a high impact on clinical disease expression. Further investigations of factors influencing the outbreak threshold of clinical signs of SM are desirable.

I read something somewhere, it might have been in this forum, that the onset of this could be attributed to the combo vaccination routine developed a couple decades ago.

I personally will be doing the individual vaccinations with our vet on our puppy, and not the combo vaccination at one time.

Hi Jeremy: absolutely not true, and this is nonsense I've seen passed around for some time by breeders who want excuses not to do what they need to be doing: MRI scanning and following breeding protocols. Instead, this handily shifts the obligation off the breeder to the pet owner :swear:, and is a totally unfounded rumour. It definitely would never have been posted here except to dismiss it!

Dogs that have never been vaccinated, or had individual vaccines, or that have had nosodes, have developed CM/SM. I have had two SM clear dogs, both of which got the combined vaccine. It is pretty clear from ongoing research that CM/SM is genetically linked with complex inheritance and some unknown environmental factors (but 'environmental factors' in this type of research, tends not to mean something as simple as say, being fed a certain type of food, and there's never been any correlation to vaccines in studies of hundreds of cavaliers now).

An earlier, very large study on MRI'd cavaliers belonging primarily to show breeders (over 500) indicated almost 100% have the skull malformation too (unfortunately) and that 1 in 4 will have SM by age 1, with about 70%+ having it by age 7+. The Danish and Dutch studies mentioned above show (yet again!) statistically, a very strong level of inheritance for SM. And interesting that the large Dutch study also shows a very high likelihood of SM by age 5; almost 60%. Many breeders had disputed that original 70%+ figure by age 7; the Dutch study certainly would confirm it.

That's why testing is so important for breeders -- the same studies indicated there's about a 75% chance of SM in any puppy from unscanned parents, and less than a 25% chance in puppies from scanned parents where breeders also follow the recommended breeding protocol (dogs over 2.5 years of age, clear of a syrinx). Not all dogs with SM will be symptomatic, especially severely symptomatic, but the level of discomfort experienced even by 'asymptomatic' dogs is likely much higher than officially believed because the worst symptom reported by humans with CM/SM is debilitating headaches, which dogs cannot tell us about. Most of us with SM dogs (and I have 5 of the 7 I've owned with it) notice many times when dogs get a certain 'look' that may well correlate to headache pain but is likely never noticed by most people. It is a frustrating, enigmatic disease in humans and dogs.

That said: I do think it a good idea to separate out the vaccines. And to follow the current (minimal) vax guidelines, which we have posted links to in the Health section. Many dogs never need another core vaccine booster after the one given at just over age 1. It's possible to just test for their ongoing immunity rather than do the vaccine as a routine. At any rate it is recommended internationally by the leading vet bodies to only vax at most every three years.

Thanks, Margaret, for posting about these new studies.

The fascinating work done by Dr Imelda McGonnell at the Royal Veterinary College on stillborn and neo-natal Cavalier puppies indicates that the skull problems leading to Chiari Malformation begin at a very early stage in the life of a foetus - long before a vaccine gets anywhere near them! Probably due to the brain and the skull not 'talking' to each other properly, and therefore a genetic source. Which makes breeding healthy Cavaliers even more complicated, given that CM is so widespread.

Kate, Oliver and Aled (both with CM/SM)