Dog owners warned to stay alert as cases of mystery dog illness expected to reoccur

Our Maltese Bichon dog is nearly covered in the falls leaves as she poses for another photo for her master.
Our Maltese Bichon dog is nearly covered in the falls leaves as she poses for another photo for her master.

Leading veterinary charity, the Animal Health Trust, is warning dog owners to stay vigilant for the signs of seasonal canine illness (SCI), a mystery illness which in recent years made a number of dogs walked in woodlands suddenly become ill.

Cases of SCI are usually seen from August to November with dogs showing clinical signs of vomiting, diarrhoea and/or lethargy within 24 to 72 hours of walking in woodland. Dog owners are advised to seek immediate veterinary advice should they see these signs in their dog following a woodland walk.

The AHT has been investigating SCI since the end of 2010 at five sites across Norfolk, Nottinghamshire and Suffolk.

Charlotte Robin, SCI Research Co-ordinator at the AHT, said: “We’ve had a fantastic response to our request for information from dog owners who have walked at our study sites, but unfortunately this information doesn’t yet point to a definitive cause.

“We’re delighted that since our investigation started fewer dogs have died from SCI.* We hope this is due to increased awareness of the condition and that dog owners now know to contact a vet for advice if they spot any of the clinical signs. Information provided to us certainly shows that if dogs get veterinary treatment quickly for SCI signs, they tend to recover within seven-10 days.

Despite no definite cause being recognised, the AHT has identified a number of common themes which may increase a dog’s susceptibility to SCI.

Charlotte added: “A number of cases reported to us have had an infestation of harvest mites. Similarly, our evidence shows that dogs which have travelled further to one of the study sites have more chance of developing SCI. At the moment we do not know if this is an effect of potential immunity in local dogs, or another factor due to dogs travelling long distances.”

The AHT is advising dog owners planning to visit woodlands this autumn to ensure that their pets are up-to-date with preventive treatments for external parasites. Products available without prescription may not offer sufficient protection against mites so please contact your local vet to discuss which options are suitable.

If you are travelling with your dog, ensure a supply of fresh water is always available and give your dog plenty of breaks from the heat of the car. Also bear in mind that accommodation such as conservatories and caravans heat up incredibly quickly and may lead to dehydration in your dog.

Charlotte said: “We cannot say for definite that travel or Harvest mites are associated with causing SCI, but ensuring your dog has access to clean water and is protected from external parasites is all part of good dog ownership. Talk to your vet about spray treatments which can be applied to feet, legs and other exposed areas of skin immediately before walking as these may offer better protection against mites than spot-on treatments. These may just help in giving your pet a better chance of avoiding SCI.”

The AHT continues to ask dog owners who walk their dogs at any of the five study sites: Sandringham Estate or Thetford Forest, Norfolk, Clumber Park or Sherwood Forest, Nottinghamshire or Rendlesham Forest, Suffolk, to complete its online questionnaire at

Charlotte added: “We desperately need information from dogs which have been walked at any of our study sites, even if they did not become ill. The information we can glean from owners of dogs who walked at the sites and didn’t show clinical signs of SCI is just as important to our investigation, as information from affected dogs.”

The veterinary charity is quick to highlight that dogs could be a risk of SCI walking at any woodland during autumn, so it advises dog owners to remain vigilant and to seek veterinary advice immediately if they suspect their dog has SCI.