Racing was rocked on Wednesday night by the cancellation of Thursday's four fixtures in Britain because of an outbreak of equine flu.
But what is the disease, and why is it so troubling for racing?
What is equine flu?:
Equine flu affects horses, mules and donkeys and is caused by strains of the Influenza A virus.
It is the most potentially damaging of the respiratory viruses that occur in UK equines and disease symptoms in non–immune animals include high fever, a dry cough and nasal discharge.
Horses with the disease can be infectious for up to ten days and it can be highly contagious.
Unlike other infectious diseases, it can be airborne over reasonable distances as well as be transmitted indirectly, including via people.
Can horses die from the disease?:
It is rarely fatal and most are on the road to recovery within three weeks. However, in severe cases it can take them many months to fully recover.
Had the three horses with the disease been vaccinated?:
Yes - and so had the eight two-year-olds affected in another outbreak in Suffolk.
That gives everyone connected with the sport a huge headache as it provides evidence of failure of vaccine effectiveness in Britain. Similar has happened in other European countries.
Have there been other outbreaks of equine flu this year?
Since the start of the year the disease has been reported in Essex, Cheshire, Derbyshire, Lincolnshire, Yorkshire and Suffolk.
However, with the exception of the racing stable and Suffolk case, all have been in unvaccinated animals.
Can humans catch it?:
There are no known consequences for humans associated with exposure to the disease.
How many racing yards are known to be affected?:
One, for definite, the stable of Donald McCain, but the full extent is unknown. The BHA is working closely with the Animal Health Trust.
When will racing resume?:
Who knows? The BHA has said it will issue a further update on racing fixtures as soon as possible. For fixtures on Friday 8 February, and the weekend of 9-10 February, e an update is expected on Thursday evening.