Clue: Spotted one in Kenya, unwell, heading off for hospital (5)
Answer: HYENA
Explanation: Spotted one in Kenya, unwell, heading off for hospital (5)
*(henya) (Kenya with the head (initial) replaced with h ("hospital") 
My only minor quibble in the puzzle, as the clue's wordplay tells us to do the anagram first, then change the initial, which is the wrong way round, but I could see what the setter intended.