A pathologist working for the Iditarod Trail Committee could not visually determine why two 5-year-old male dogs in Wasilla rookie musher Lou Packer's team died, the committee said today in a press release.

Rescuers who pulled Packer from the trail about 22 miles north of the ghost town of Iditarod in the desolate and frigid Innoko River country found the two dead dogs, Dizzy and Grasshopper, with Packer -- along with 13 dogs still alive. Exactly when the two perished and what caused their death is not yet known.

Packer was flown to Unalakleet and has scratched from the race.

Further testing on Dizzy and Grasshopper, including a histopathology, which examines microscopic changes in organs due to disease, is expected.

Packer was part of a group of three back-of-the-pack rookies who ran into trouble after leaving Iditarod on the long 65-mile run to Shageluk. The other two, Blake Matray of Two Rivers and Kim Darst of New Jersey, also scratched.

Packer, 55, was born and grew up in California, receiving his medical degree in 1981 after studying at UCLA and the UC-Berkeley.

He moved to Alaska 22 years ago and runs Urgent Care at Lake Lucille.

"I watched the seventh Iditarod start when the pope came to visit," he wrote in his official Iditarod biography. "I realized it was a sign from the heavens above that I should run the Iditarod. After all, dog (spelled) backwards is GOD.

"Being immediately hooked, I ran a couple of other people's dogs a few times and each time my craving for dogs got worse and worse."

He started seriously training dogs in 2006.

He and wife Ellen have three children: Avalon, 10, Cirrus, 7, and Gazelle, 5.