North Carolina health officials are investigating the death of a woman who died last week of a flesh-eating bacteria three days after accidentally jamming her hand in a wheelchair while working at a nursing home.

Nursing assistant Sharron Bishop, 44, died Feb. 27. A doctor said a rare flesh-eating bacteria may have entered her body through a thumb injury and she turned from healthy to fatally ill.

The culprit was a rare invasive form of group A streptococcal bacteria, said Debbie Crane, a spokeswoman for the state Department of Health and Human Services. The noninvasive form is widespread and is commonly known for causing strep throat, she said.

"It's kind of like getting bitten by a shark or struck by lightning," she said. "It's not something that spreads to the community."

North Carolina gets about 125 reports of the invasive form of strep annually, and about 10 percent are fatal, she said.

David Bishop said doctors at UNC Hospitals, where Sharron Bishop died, have told him it's impossible to know how his wife contracted the rare infection.

"The UNC doctors said she could have picked it up at the gas station, at the grocery store, anywhere," he said. "We will never know."

Sharon Bishop complained on Feb. 24 about a swollen thumb. She had jammed it at work and worried that she had dislocated it. David Bishop took her to Betsy Johnson Regional Hospital, where doctors gave her pain medication and sent her home.

The swelling got worse. By the morning of Feb. 27, her arm was twice as large as normal and looked like it would burst, David Bishop said. Fluid leaked from her elbow and wrist. She complained of terrific pain.

Dunn physician Abraham Oudeh diagnosed necrotizing fasciitis, an infection that destroys tissue.

Doctors at UNC Hospitals that evening tried to stop the spreading infection by amputating her arm at the clavicle and removing all the muscle and tissue around her left breast, torso and thigh in a futile effort to save her life.

Harnett County Health Director John Rouse Jr. said Bishop's was one of two confirmed cases of the bacteria that his office investigated in recent days after being notified by state health authorities. He said he believed the other woman, whom he also did not identify, knew Bishop.

Rouse said it would be impossible to determine whether they passed the bacteria to each other. Rouse said the other woman is recovering.