Dutch Olympian Adelinde Cornelissen was one of four members of The Netherlands' team dressage grand prix team, but she made the incredibly difficult decision Wednesday to end her participation in the Olympic Games early after her horse, Parzival, was bitten by an insect and became ill. Cornelissen posted her story to Facebook.

Via Facebook:

"The first days in Rio went according to plan: a relaxed flight, stabling good, training good. Parzival feels happy and fit.

More from FoxSports

Until yesterday morning... I planned to train early on Tuesday morning, so I was at the stable at 6am. Saying good morning to Parzival, I saw the right side of his head was swollen, he had been kicking the walls. I took his temperature:he had a fever of over 40 degrees Celcius, but he still didn't look sick. He was eating and drinking and while walking I had a hard time keeping up with him, as always...

Jan Greve came right away and after double checking with the vets here they concluded he was bitten by an insect or spider or some sort of animal which produces toxics.

To get the toxics out of his system we gave him fluids. From 6.30 to 15.45hrs we kept him on this. It helps the kidneys to clean up the toxics out of the body. The vets at the clinic took swaps from the nose and checked the blood. The temperature dropped gradually and by 15.30 it was 38.4... We then took x-rays from the jaw and echoed the area. Just making sure.. All ok."

Cornelissen slept in the stable with Parzival overnight to keep him company.

"Then difficult descisions came... We requested the FEI if we could swap starting places within the team, so Parzi could get a day to recover. Competing on thursday in stead of wednesday. But the FEI declined.
At that point I didn't want to compete anymore... Parzival's health is more important than anything else in this world!

I slept at the stables, checking up on Parzi every hour... I was not going to leave him alone! Of course I didn't get any sleep...

Main thing, this morning temperature had dropped to 37.5! And the swelling again had come down a bit."

Parzival's health continued to improve, but Dutch team didn't have any reserves to step in for Cornelissen, which complicated her decision.

"I had decided yesterday I was not going to compete, but now the temperature was back to normal, he looked fit, was eating and drinking good, I also didn't want to let the team down... In the back of my mind knowing we had no reserve combination here..... What to do?

Between 7am and 8am we were allowed to ride in the arena.
I discussed with Jan Greve and Johan Rockx and decided we were going to walk and trot under saddle for 10 min and see how he was...

And so we did... We went to the arena, rode a few laps and he looked happy and fit."

Ultimately, Cornelissen felt that although the vets cleared Parzival to compete, she didn't think her horse was 100 percent healthy.

"Questions questions... What is wise? I discussed with several vets and the team coach.. The FEI vets came and checked up on him around 10am. All gave green light to compete.. We decided I would give it a try. The fever was down, which means the toxics are out of his system. There is still a bit of swelling in the jaw, but we cooled it all the time and the swelling gets less.

I agreed to give it a try. Knowing the story, I took it easy in the warm up and didn't want to ride full. He was ok, although he didn't feel very powerful. Normal of course after a day like yesterday. I walked a lot to save the energy.. When I entered I already felt he was giving his utmost and being the fighter he is, he never gives up... But in order to protect him, I gave up...My buddy, my friend, the horse that has given everything for me his whole life does not deserve this.... So I saluted and left the arena."

You can read her entire story on Facebook.