But more staff, including a psychologist, who will treat people affected by post-traumatic stress disorder after seeing loved ones die, and a water and sanitation health expert, will fly out over the next few days.

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"The exact cause of death has not yet been established, but it's quite clear that Knut didn't die in a situation of stress, " Mr Blaszkiewitz said.

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"Sadly many will retire before that because they are either injured, they die or they suffer from the stress of the job, " he said.

BBC: Police officers (unidentified)

Most manatees die from collisions with watercraft or from "cold stress" in chilly waters, Baxter said.

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