Three Yukon mushers and their dog teams will compete in Alaska's Iditarod race, which starts this weekend.

They say one of the biggest challenges this of year's long-distance, sled-dog race has been overcoming sickness in the dogs. Sometimes dogs pick up an infection, bacteria or virus when they come in contact with large numbers of other dogs, like at races. 

"This year, it was very nasty," said musher Hans Gatt. "I have to say it just carries on, you know, forever it seems."  

Marcelle Fressineau's kennel was also hard hit this winter.

"The young dogs were infected by the virus but I gave them rest and after it was OK," she said.

Musher Michelle Phillips says this year was nothing unusual for her team.

"Every year there's viruses going around; that's part of mushing," she said. "Yeah, my dogs have gotten sick. It's another reason why we go to early races so the dogs are exposed to those. That's just part of running dogs."

Veterinarian Dr. Jessica Heath says it can be difficult to know if the dogs are all sick from the same cause. 

"Usually we have to do a lot of diagnostic tests in order to know what a dog is sick with," she said.

Doing that for an entire kennel is expensive.

"For a musher who's usually got 40-60 dogs in a kennel, it can be prohibitively expensive for them ... to figure out exactly what disease they have," said Heath.​

Heath says the good news is you don't always have to know exactly what you're dealing with in order to treat dogs and make them feel better.

The Yukon teams are in good health at the moment and will join the other 66 teams at the Iditarod. The ceremonial start is in Anchorage on Saturday and the competitive race begins Sunday at Willow, Alaska.