A contagion of ill fortune appears to be sweeping through Europe's top middle-distance horses.
A day after Danedream was confined to Cologne by quarantine regulations, leading British contender Nathaniel joined the defending champion on the sidelines for Sunday's Prix de l'Arc de Triomphe.
According to trainer John Gosden, Nathaniel is running a temperature and will not be able to run at Longchamp. It is an unhappy ending to a story that had promised a very different sequel when Danedream and Nathaniel fought out a gripping finish to the King George VI and Queen Elizabeth Stakes at Ascot in July.
The Arc had already lost Snow Fairy to a setback last weekend and on Monday connections of Danedream were abruptly stranded by an outbreak of swamp fever in her German training centre.
These serial defections are making it very hard for the men round Camelot's table to resist the Arc. A final decision is expected after Aidan O'Brien has worked the Derby winner at Ballydoyle this morning.
"Obviously, we're looking at it (the Arc) very strongly with the two big horses, Camelot and St Nicholas Abbey," O'Brien revealed last night. "Both of them are doing a little bit in the morning and if they come through that well, I think everybody will sit down and have a chat about it and we'll see what we're going to do.
"It would be great if both of them ran, but, obviously, they have to be well and they have to go through all their tests and pass all those things before they get the all-clear, but we'd be looking forward to it if that could happen."
A silver lining will also be perceived at Ascot, where opposition had seemed worryingly scarce for Frankel in the Qipco Champion Stakes on October 20. Nathaniel is especially effective round Ascot and will presumably be diverted there, if restored to health.
Even second place in so valuable a race could sway the trainers' championship, though that will seem the coldest of comforts for Gosden right now.
Danedream, in contrast, cannot leave her home course for 90 days. Patrick Barbe, racing manager to Teruya Yoshida, duly accepted that there was no point even confirming her entry.
"Nothing can come in and out for three months," he said. "That situation at the moment is final and binding. If the race was in two weeks, they might have found a solution, but with time being so short it has proved too difficult."
An intriguing factor in the Camelot decision is the dilemma over his rider. Camelot is set to carry 8st 11lb -- 2lb below the reluctant minimum of O'Brien's son Joseph, who has been earmarked for the ride on St Nicholas Abbey.
The Ballydoyle supremo has already stated that Camelot would need a new jockey, barring the removal of a limb, but his patrons may consider one or two of the alternative solutions almost as drastic.
With Ryan Moore set to be claimed for Sea Moon, they may well turn to one of the stable stalwarts. Admittedly Seamus Heffernan had an unhappy experience on So You Think in last year's renewal, but Colm O'Donoghue reliably seizes every chance he is given and is now seasoned at this level.
Otherwise John Magnier and his partners at Coolmore could conceivably contemplate burying past differences with Frankie Dettori, whose availability belies his status as one of the all-time masters of Longchamp, a notoriously challenging circuit.
Dettori has long served Coolmore's great rival, Sheikh Mohammed, and even expressed contrition after accepting the chance to win the 2005 St Leger for O'Brien on Scorpion.
But the Sheikh would surely owe Dettori greater indulgence this time round, after promoting young Mickael Barzalona to share the Italian's role at Godolphin.
Japanese challenger Orfevre, winner of the Prix Foy, has strengthened as favourite at around 5/2, with a field of 17 currently in the race following the latest scratchings stage.
There is a supplementary stage tomorrow at which Saonois, winner of the Prix du Jockey-Club and Prix Niel, is expected to be added.