Veterinarians say now is the time of year pet owners need to be vigilant, especially after a rare illness killed a dog earlier this week.
The disease is called Pythiosis - it's a fungal disease that animal experts want you to be aware of.
If it's not their toy or treat, and if it's not their food or water, veterinarians say you'll want to pay attention to what's going in your dog's mouth.
Their latest example of Pythiosis is Samson; when the Oklahoma Alliance for Animals took him in last week they thought he was starving to death.
"I have never seen a dog that way, that thin," said OAA president Jamee Suarez.
But lab tests revealed Samson actually suffered from Pythiosis.
"I thought, 'What is that,' you know? It sounds crazy," Suarez said.
Dr. Khris Keller helped treat Samson and said, "I've been at it for 36 years and he's the third dog I've seen with Pythiosis."
He said dogs get Pythiosis by ingesting a mold that grows in swampy waters. The fungus causes their intestines to thicken so they can't keep food down.
"The vomiting and diarrhea for a long period - you know, more than 24 or 48 hours - that needs to be checked out,” he said. “The extreme weight loss in this case was the big - and the dog was very happy, he wasn't depressed."
The disease is so rare, Keller said there's no reason not to take your dog to the lake this summer, but you'll want to mention it to your vet if your dog starts showing symptoms so they can run tests and catch it early, avoiding the death that Samson suffered.
"It's a sad, sad thing for that dog. And there could be more that appear that way," Suarez said.
Veterinarians say humans can also get Pythiosis but that you can't catch it from your dog.