Salmon Poisoning Disease – A Fisherman’s Dream or Nightmare?

If you’re like me, you’re here because you love Oregon.  We try to keep it a secret, but the word is out.  Oregon is home to fresh air and clean living with beaches, rivers and creeks just a step away.  If you’re lucky, you get to enjoy the salmon as well, either as fisherman, streamside hiker or on the dinner plate.  There is something special though about our fish that you won’t see on the visitor’s brochure.  This is possible in all salmonids (salmon, trout and steelhead) in the Oregon, Washington and Northern California waters.

I’m referring to Salmon Poisoning Disease (SPD).  This potentially fatal illness is caused by a microscopic parasite (Nanophyetus salmincola) in the fish that harbors bacteria (Neorickettsia helminthoeca), in much the same way that ticks can contain Lyme Disease.  The parasite is ingested when dogs eat or lick the raw fish.  About 1-2 weeks later we start to see the common symptoms of appetite loss, fever, diarrhea and swollen glands.

Our diagnosis depends on identifying the parasite eggs (microscopic) in a stool sample.  The treatment involves medicines to remove the parasites, antibiotics to treat the bacteria, and fluids to restore/maintain hydration.  Most dogs that are treated will have a complete recovery.  And what’s better, they usually become immune to SPD for life.

This time of year the fish are in the rivers and we are seeing cases of SPD almost weekly.  So if you are down by the water with your dogs, or bringing fish back home, remember to watch for signs of SPD.

-Ryan Frome, DVM

 

Frequently Asked Questions

How can I tell if my dog has Salmon Poisoning Disease?

Common symptoms include appetite loss, fever, diarrhea and swollen glands within 1-2 weeks of exposure to raw fish.  However, there are many other illnesses that can mimic SPD, so it is important to identify the parasite eggs in a stool sample.  Without a definitive diagnosis the proper treatment for other diseases can be delayed.

I’ve heard that people can feed their dog raw fish to make them immune to SPD.  Is this true?

This practice, commonly known as ‘Fishing a Dog’ is controversial.  The benefit of having a dog that has recovered from SPD is that they are usually immune for life.  That means you can take them to the river and not worry as much about them eating a fish that washed up on the bank.  Unfortunately, this can be very dangerous to your dog.  Raw fish can contain other diseases that make dogs sick.  We also suspect that not every fish contains the parasite that causes SPD.  Therefore, you may have a false sense of security and delay future treatment when your dog truly has SPD.  Lastly, we have seen dogs that were treated with antibiotics from non-veterinary sources that did not respond and proper treatment was delayed for many days.  This has been due to improper dosages, incorrect diagnosis, or ineffective antibiotics.  So if you are interested in ‘Fishing Your Dog’, it is best done in cooperation with a veterinarian familiar with SPD.