1.   To be sure, scientists have created disease by inoculating animals with brain tissue from infected animals.

2.   But when the scientists inoculated animals in the laboratory with blood samples taken from the woman, they isolated a virus that they were unable to identify.

3.   Instead, investigators inoculate animals with brain tissue from infected animals, tissue that contains prions but that may also contain viruses.

4.   Gill said inoculating animals was an imperfect solution that could be used to buy time while officials slaughter livestock in hopes of stopping the disease.