Whether she was hiking in the woods, growing organic vegetables or working on her master's degree in psychology, Aimee Copeland embraced her passions with determination and a constant smile that made friends wonder if she ever had bad days.

Now the 24-year-old Georgia graduate student is fighting to survive a flesh-eating bacterial infection that forced doctors to amputate most of her left leg. They warned she would likely lose her other foot and both hands.

Her parents and sister remained at her side Saturday after a week at an Augusta, Ga., hospital, while friends 200 miles away at the University of West Georgia in Carrollton are holding vigils and organizing blood drives while praying for Copeland to recover.

Copeland had just finished her second year of graduate school and soon to begin work on her thesis when she was injured. It happened on a kayaking trip May 1 with friends when she tried to cross the Little Tallapoosa River on a homemade zip line. The line broke and Copeland fell onto the rocks below, suffering a nasty gash in her leg.

Doctors at the local emergency room closed the wound with nearly two dozen staples, but it became infected within a few days. On May 4 she was diagnosed with necrotizing fasciitis and flown to Augusta for treatment by specialists.

Infections by so-called flesh-eating bacteria are rare but sometimes can run rampant after even minor cuts or scratches. The bacteria enter the body, quickly reproduce and give off toxins that cut off blood flow to parts of the body. The affliction can destroy muscle, fat and skin tissue. Affected areas may have to be surgically removed to save a patient's life.

Copeland's family said she suffered cardiac arrest a week ago when her leg was amputated. She was transferred to Doctors Hospital in Augusta, where she remained in critical condition Saturday. She was conscious after spending most of the week unconscious.

"Aimee is alert and trying to mouth questions," her father, Andy Copeland, wrote on a website created to provide updates to friends and supporters. "Her breathing tube has been reoriented to increase her comfort and allow them to try to read her lips. She said: 'I can't talk!' We told her it was because of the tube, and we explained the need for it. 'Take it out!' She also asked 'What happened?' and 'Where am I?'"

"I thought it would be better when she became alert," Copeland's father wrote, "but it is actually harder for us."

Despite the severity of her condition and the likelihood she will lose all of her extremities, Copeland's family has remained upbeat about her prospects for survival after doctors initially told them her chances were slim to none.

Those who know her say Copeland has the right mixture of tenacity and a positive attitude to overcome.

Donadrian Rice, chairman of the psychology department at the University of West Georgia, said Copeland is always quick to help undergraduates. He noted children visiting department offices are automatically drawn to her.

"She just tended to be the kind of person who always looks at things from the bright side and did that without any effort," Rice said. "I always felt that even during the lowest moments of her medical condition. She would fight, she would survive."

LaFleur said he once asked Copeland if she had ever had a bad day as they worked together on a tedious project. While he grew frustrated, Copeland just kept smiling.

She is a notoriously healthy eater, he said, who grows her own organic foods and typically snacks on a mix of nuts and raisins that she prepared at home - "her own concoction, definitely not trail mix."

"Aimee was still sort of trying to decide what she wanted to do, but one thing she was very interested in was letting people find their own way through life, their own path," LaFleur said. "She always tried to find ways to help people."