"Less than 1% develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues), " it said.

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"Less than 1% develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues), " the CDC said.

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Federal guidelines published last year for evaluating organ donors with encephalitis urge "extreme caution" if the suspected cause is a viral pathogen, such as rabies.

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