EO PRA – a newly identified inherited condition in Spanish Water Dogs
For members who don’t know us, we are Rachel (Breed Health CoOrdinator) and Jenny (Hon Secretary) and we want to give you all some more information about why we will be putting forward a recommendation at the AGM postal ballot that dogs being bred from should be tested for a new form of PRA which has now been found in Spanish Water Dogs bred in the UK.
The condition was identified and a test developed in 2020 through the efforts of Dr Petersen-Jones' lab at Michigan State University and the SWDCA (Spanish Water Dog Club of America).
What is EO (Early Onset) PRA (Progressive Retinal Atrophy)?
EO PRA usually starts with night blindness of young dogs, around 1 year old, progressing to less and less ability to see, in both dim and bright conditions, resulting in blindness before the dogs are 4 years old. The condition is not a painful one, so it has been difficult to detect in its early stages. That is, until now… a DNA test can be done as soon as a puppy has a microchip.
As a matter of interest, EO PRA has just (Dec 2020) been discovered in the SWD’s close cousin, the Portuguese Water Dog (although it has the same effect, it is not caused in exactly the same way as in SWDs), and already occurs in several other breeds.
What’s the difference between EO PRA and prcd PRA?
Unlike the first prcd PRA discovered some years ago in Spanish Water Dogs, which results in blindness later in life, EO PRA is, as the name suggests, a different inherited form of PRA which affects Spanish Water Dogs early in life, rendering them blind between the ages of 2-4 years’ old.
How do dogs get EO PRA?
Both PRA conditions in Spanish Water Dogs are inherited recessively (ie both parents need to carry a copy of the faulty gene for a puppy to be born AFFECTED), so acting upon the results of DNA testing reliably prevents the condition from spreading throughout the breed. This means this is not an environmental condition, i.e. a dog does not get EO PRA from trauma or from the way it is brought up, it all depends on its breeding.
So far, we know of 6 cases here in the UK which been tested CLEAR for prcd PRA but AFFECTED or CARRIERS for EO PRA.
In summary:
Dogs DNA tested as CLEAR will not get the EO PRA condition at any time in their life
Dogs DNA tested as CARRIERS will not get the EO PRA condition at any time in their life
Dogs DNA tested as AFFECTED will almost definitely get the EO PRA condition, and become blind by the age of 4. The scientists who developed the test in the US say that so far, ALL AFFECTED dogs have become blind.
We fully expect that many dogs used for breeding in the UK will test CLEAR for the condition, but as the condition has such high impact for the dogs and owners involved, we feel that testing is now the way ahead.
How can we prevent the condition spreading?
The best way forward is that all dogs that are bred from are tested and we ensure AFFECTEDS or CARRIERS are always bred to CLEARS. In order to eradicate this condition even more quickly, we could choose to exclude CARRIERS from the breeding population, with the small numbers so far, this could potentially eliminate the condition in our population within a few generations.
Given the small numbers of AFFECTEDs reported so far (2), we are very much hoping that once all breeders start to test, we will be able to identify how widespread the condition has become in the UK. The Spanish Water Dog Club of America is also recommending the same testing.
However, we cannot be complacent- there are lots of imports every year of Spanish Water Dogs, so if the condition is not tested for elsewhere, it could easily be brought back into our breeding population, so we need to test to monitor this condition.
Getting a test:
It is easy to have your dog DNA tested. If you are a member of the SWDC, you can contact the Hon Secretary for a form for discounted testing at Laboklin, a UK based laboratory. You then contact them for a ‘testing kit’ and you send in a swab or blood for testing. It is very simple to do a swab for your dog and Laboklin send instructions with their kits.
Living with a blind dog
Sight is a dog’s third most important sense, after smell and hearing, so even blind dogs can cope exceedingly well with their condition, however it is caused.
Please click on the link below to read a touching case study of an SWD owner and her dog living with EO PRA.
Jennifer Hall has given permission for us to share her poignant story of how she and Tia live on a day to day basis with her blindness.
Breed Health Committee recommendations:
Our recommendation is that we add this DNA test to the SWDC Code of Ethics and this proposal will be sent out to all eligible members as part of the Club’s AGM postal ballot.
SWDC testing discounts for members:
We have an offer on the bundle of previously approved DNA tests for SWDs (prcd PRA, NAD, CHG, DM, Brachyury) with Laboklin and the new EO PRA test is also available at a discounted rate. We are in negotiation with the laboratory to expand the current breed bundle to include this test. Dogs already DNA tested for other conditions can be tested for just this condition.
For an individually numbered discounted test form, please contact Hon Secretary Jenny Abrahams at:
Rachel Cooper & Jenny Abrahams, SWDC Health Sub Committee
Thank you Jennifer Hall for sharing your experience of your lovely girl Tia - I hope its gives comfort to anyone worried about their dogs potential loss of sight or indeed a testament of relief to those already living with a blind dog.