Dog in the woods

Seasonal Canine Illness (SCI)

  • SCI is a rare illness which has dramatically declined in numbers since 2010
  • No-one understands the cause of SCI and there is no cure
  • The key symptoms of SCI are vomiting, diarrhoea and tiredness within 72 hours of being in a woodland area. However, this rare condition is not the only reason why these symptoms may be seen; there are lots of other common causes for these symptoms.
  • If you suspect your dog has SCI, please contact your vet as soon as possible


This mystery illness affects dogs of any size, shape, age or gender.

The important thing to bear in mind is that SCI is incredibly rare and only seems to affect dogs in the autumn, with more cases being seen in September than any other month.

What are the symptoms of SCI?

The symptoms of SCI are usually seen within three days of being in a woodland area. Your dog will normally exhibit the following behaviours:

  • vomiting
  • diarrhoea
  • tiredness

What should I do if I suspect my dog has SCI?

Should you suspect that your dog is exhibiting signs of SCI you should contact your vet immediately, especially if it is within 72 hours of visiting a woodland area.

Is there a cure for SCI?

Due to researchers not understanding the cause of SCI, there is unfortunately no specific cure. However, some of the symptoms can be alleviated, which means that if your dog receives vet attention quickly most will recover from SCI.

How serious is SCI?

In some rare cases, SCI has been known to be very severe and sadly some dogs don’t survive.

However, the exact number of cases is unknown because there is no known cause.

Luckily, research carried out by the Animal Health Trust suggests that there’s been a decrease in the number of fatal cases since 2010.

What can I do to reduce the risk of my dog getting SCI?

Owners should be sure to closely monitor their dog after they have been on a woodland walk. You can try using the following measures to help reduce the risk of your dog getting SCI:

  • keep your dog hydrated
  • use preventative spray against mites before you walk your dog. Research suggests that harvest mites are commonly noted on dogs suffering with SCI, which means that using preventative spray could potentially help prevent the illness.
  • if your dog is unwell please contact your vet asap and it may be worth mentioning any woodland walks within the last few days. Visiting your vet at an early stage could be the difference between life and death.

NOTE: At present there are no products licensed for treating harvest mites in dogs, but there is some evidence that Fipronil spray applied to the whole body may be effective.




— Page last updated 10/09/2019