Defending Quest champ Lance Mackey is trying for a third top finish in the long distance race. ((CBC News))

A second sled dog in the 1,600-kilometre Yukon Quest race died Monday morning on the Yukon River between the Slaven's Cabin dog drop and Circle City, Alaska.

The five-year old male dog, named Melville, was running in the team of Alaskan musher Brent Sass.

Race officials say the dog's body was flown to Central where a necropsy will be performed.Results will be released within 24 hours.

Earlier in the race, Japanese musher Yuka Honda had a dog choke to death on its own vomitafter she lost her team.Sass came to her rescue, giving her a ride until they found her team stopped on the trail along with the dead five-year-old female named Jewel.

Meanwhile frontrunner Lance Mackey continues to lead the race to the finish line in Fairbanks, having crossed the treacherous Eagle Summit Monday before heading on the Chena Hot Springs checkpoint.

The 36-year-old cancer survivor is hoping to win histhird straight race,picking up$40,000 US of the total purse of $200,000 US.

His closest competitor is three-time winner Hans Gatt, of Atlin, B.C., who crossed the summit later in the day with his eight remaining dogs.

Mackey, who still has 11 of the 14 dogs he began the race with in Whitehorse on Feb. 10,has been slowly widening the gap between them since leaving Dawson City Friday.

Whitehorse-area mushers William Kleedehn, Gerry Willomitzer and Michelle Phillips are runningthird, fourth and fifth respectively.

Six of the 28 teamshave scratched including Yukon musher Frank Turner, who has entered 23 of the 24 Quests. He pulled out after reaching Dawson City Friday.

Honda, who continued on for several days afterher dog died,also decided to call it quits when she reached the Klondike midway point.

Musher Greg Parvinof Nome, Alaska, withdrew in Dawson City on the weekend after his team quit on him en route from the Stewart River checkpoint.

Another Alaskan, J.T. Hessert, was withdrawn by race officials because he did not have a handler to drive his truck but he continued on down the trail nevertheless.

Yukon mushers Catherine Pinard and Kiara Adams withdrew earlier at Pelly Crossing.