Sled dog lighter sled dogs." Outside of Alaska, dog-drawn carts were used to haul peddler's wares in cities like New York. In 1925, there was a diphtheria outbreak in Nome, Alaska. There was not enough serum in Nome to treat the number of people infected by the disease. There was serum in Nenana, but the town was away, and inaccessible except by dog sled. A dog sled relay was set up by the villages between Nenana and Nome, and 20 teams worked together to relay the serum to Nome. The serum reached Nome in six days. The Iditarod Trail was established on
Iditarod Trail Sled Dog Race reveals the results of tests on the dogs. Each team is composed of twelve to sixteen dogs, and no more may be added during the race. At least five dogs must be on the towline when crossing the finish line in Nome. Mushers keep a veterinary diary on the trail and are required to have it signed by a veterinarian at each checkpoint. Dogs that become exhausted or injured may be carried in the sled's "basket" to the next "dog-drop" site, where they are transported by the volunteer Iditarod Air Force to the Hiland Mountain Correctional Center at Eagle River