Trainers and racecourses have been told to be on guard after it was revealed Victor Dartnall's Devon stables have been temporarily shut down following an outbreak of equine herpes virus in the form of equine neurological disease.
Dartnall, whose stables are at Higher Shutscombe near Barnstaple, had runners as recently as Saturday at Wincanton, while his last winners came at Exeter and Chepstow earlier this month.
It is possible his horses may have been carrying the disease before they showed any symptoms and while it is difficult to spread, the British Horseracing Authority is taking every precaution to keep the outbreak under control.
In a statement, Professor Tim Morris, BHA's director of equine science and welfare, said: "We have been working with the trainer and his veterinary surgeon to ensure that the correct, robust security measures have been put in place.
"It is in theory possible that horses may have been infectious before the signs of the disease appeared. We have therefore alerted racecourse, trainer and veterinary representatives to possible exposure, but stress the actual risk of transmission of this virus in a controlled raceday environment is relatively small.
"This emphasises the importance of trainers being vigilant for signs of disease and in particular they should refer to the NTF Code of Practice for Infectious Diseases of Racehorses in Training, which contains specific advice on surveillance and what to do if they have concerns that a horse in their care is showing signs of the disease."
A statement on behalf of Dartnall said: "Over the last few days we have suffered an outbreak of a neurological disease in some horses. Initial test results support the cause to be neurological herpes virus. We are working very closely with our vets and the BHA and we are hopeful that we have the situation under control."
BHA spokesman Robin Mounsey said: "Obviously no entries can be accepted from the stable until the outbreak is cleared.
"The racecourses where Victor's horses have raced in the last couple of weeks have been informed. They will carry out their own procedures for ensuring the racecourse is completely clear of infection.
"They are precautionary as it is a very difficult disease to spread. Everything is being done as a matter of thoroughness. It is dreadful news for Victor's yard. For racing it is an issue that is very easily contained. Victor has done everything spot on. He's quite distraught and it is very sad news for him."
24 October 2014Sir Max clinches Mercury gold
Full marks for Bangor schooling
Milky Way on another planet
O'Brien targets another Trophy
Hurricane in hat for Morgiana
Buick happy as a Star is born
King ace back in the Old routine
Ballyalton out for the season
McCoy makes Chepstow return
Hutchinson sits out weekend action
Botti seeking Astrelle celebration
Balding sweet on Park chance
Walker hoping for Glorious victory
Times out to make Newbury headlines
Cheltenham honour leading figures
Moore keen on Adelaide chance
Stevens back for Breeders'
Johnson Houghton fined
Duke lords it at Carlisle
Southwell first for O'Brien
Fenton fined over steroids
Buywise on the money at Ludlow
Lockinge the big plan for Toormore
Stone ruled out of Old Roan
Wetherby likely for First run
Elm tops Trophy octet
23 October 2014Fenton guilty of drugs possession
Williams hoping for Max power
Harty biding his time with Lane
Clonmel aim for Baily
Jezki possible for Morgiana bow
Harrington expects Naylor to shine
Gosden a Fan of Newmarket scorer
Northern aces face off in Cumbria
Murphy plagued by shoulder injury
Dynaste charts direct Haydock route
O'Brien outlines Breeders' plans
Wetherby-bound Taquin to duck Power
High hopes for Adelaide run
Gilgamboa waits on ground
Dandino misses Cup date
22 October 2014December date for Balding memorial
Deputy outgunned at Fontwell
Whisky chasing Power spoils
Burke maps out Odeliz targets
Present sights set on Power prize
New category for all-weather champs
Moviesta has sales date
National aim for O'Neill star
Cheltenham on Ginge agenda
Lewis eyeing Dubai success
Henderson handed Ascot role
Panther given Breeders' go-ahead
Plain sailing for perfect Storm
Big Easy sets sail for Open fixture
Hall monitored for Giant Bolster
Stomachion in November frame
Hughes revels in 'sweet' success
BHA moves to address small fields
Connell turns to Heskin
Integral to race on next year
21 October 2014Storm breezes to Exeter victory
Moore concedes title to Hughes
Meade maps out gameplan for stars
Pele poised to tackle Hennessy
O'Neill sure of Taquin redemption
Heron seeking Great prize
Court to go on Trial
Saviour blow for Skelton
Dan makes chase debut
Moore waits on Grugy decision
O'Neill outlines That choices
Conn possible for Auction bid
Power team weigh up options
Bangor cancel schooling card
No rushing back for Long Run
Dynaste leads Old Roan contenders
Grands Crus retired
Exciting Berlais heads to Chepstow
Force handed Hong Kong mission