Parzival was bitten by an insect or another animal, leading to a fever from the toxins, Cornelissen said on Facebook.
“It started yesterday morning,” Cornelissen said. “I came to the stable, and his cheek was completely swollen. It appeared that he was bitten by a spider or a mosquito or whatever, so his body was full of toxic fever."
Cornelissen and Parzival won individual silver and team bronze in 2012.
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