Trainer Simon Crisford says there's no obvious connection between his horses and the 6 others that have tested positive for equine flu.

Four horses at Crisford's Newmarket stable have been struck by the disease which has shut down racing in the UK

Six horses at Donald McCain's yard in Chesire - which is 170 miles away - tested positive last week.

Crisford’s horses have not had an evident point of contact with McCain’s in the past fortnight.

The lack of a link will increase concern among officials that the airborne disease may spread.

Crisford was one of the 174 stables to be placed in lockdown - because he had a runner at Newcastle last Tuesday.

The horse in question, Sajanjl was subsequently cleared of the virus.

Four new cases of equine flu identified

Crisford said in a statement released on Monday: "None of the four horses that have returned positive tests for equine influenza displayed any clinical signs of respiratory illness, including nasal discharge and elevated temperatures, prior to the mandatory swabbing that was undertaken last Friday, February 8.

"The swabbing occurred following Sajanjl's race at Newcastle last Tuesday, February 5, and she has tested negative. There is no obvious connection between Sajanjl and the four identified horses.

"All horses at Kremlin House Stables, totaling 92 boxes, undergo a strict vaccination check and programme on their arrival.

"All four identified horses have been vaccinated within the last six months along with the rest of the yard and in line with vaccination protocol."

Horse Racing Ireland says racing will continue here in the meantime as the disease risk status in racing Thoroughbreds has not yet changed.

An expert says the equine flu outbreak which has brought horse racing to a halt will be hard to stop spreading.

Hattie Lawrence is the Clinical Director at Valley Equine and acts as veterinary surgeon at Kempton, Sandown and Epsom:

“This is an airborne virus which means it doesn’t matter how good the yard bio-security measures might be, how careful people might be about washing their hands for example.

“It can still be transmitted from horse to horse just on the air.”