She landed two master's degrees in public health, then worked for nonprofits, including Flying Doctors of Africa, descending on hot spots in Rwanda and elsewhere.

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Among a wide field of potent prescription painkillers -- which the Centers for Disease Control and Prevention says are fueling an epidemic of abuse in the United States -- hydrocodone may have been flying under the radar among doctors.

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He said doctors advised them against flying and they decided the ship would be a good place to recuperate.

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"For health reasons, his doctors said he should not be flying at the moment so he's decided not to attend, " Holt said.

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