Horton had been due to arrive in Jersey early next week in time for the road race and town criterium, after competing in the National Championships this weekend for his team Madison Genesis.
He was overwhelming favourite to win that criterium for a fourth time and would also have been defending his crown in the road race.
Tanguy, who is a close friend of Horton, said: ‘Looking at it in a selfish way, it’s obviously good news for Jersey but it’s such a shame.
‘It’s absolutely gutting when someone misses out on an opportunity like this and I’m quite upset for him … he’s a close friend of mine and I’m gutted for him.’
He added: ‘Tobyn was a known quantity but now the events have been blown wide open, if you like. We don’t know who the other islands are bringing and we don’t know what will happen.’
Speaking yesterday, 28-year-old Horton expressed his disappointment at being ruled out, but says it was the best decision in the interests of everybody in the team.
‘Since the Tour Series finished just under a fortnight ago, I have only been able to get on the bike to train once because this virus has prevented me from doing so,’ he said.
‘I couldn’t offer any guarantees at all that I would be fit for the Games and it wouldn’t have been fair on anybody if I waited any longer and then had to pull out the day or so before a race.
‘This way, it gives the opportunity for whoever is chosen as my replacement to at least have a few days’ warning and I know that the quality in the team means they will still perform fine in my absence.
‘I am bitterly disappointed because representing Guernsey always means everything to me, but unfortunately these things happen, people get ill from time to time and I have to accept it.’
The Island Games cycling competitions begin on Sunday morning, with the men’s and women’s time trial events starting and finishing at Red Houses.
