Since the incubation period for equine influenza can be up to 72 hours, samples will be taken on Friday from horses that raced at Ayr and Ludlow and sent to the Animal Health Trust in Newmarket for analysis.
David Sykes, director of equine health and welfare at the BHA, added: "We would like to thank Donald McCain for his co-operation in this matter, and for the responsible manner in which he has dealt with this issue, under the guidance of his veterinary surgeon".
All of Thursday's racing at British racecourses was cancelled late on Wednesday night because of an outbreak of equine influenza, the first time such drastic action has been taken since the foot and mouth crisis in 2001.
Equine influenza is a highly infectious disease of horses, mules and donkeys occurring globally caused by strains of Influenza A virus.
LeBron critical of Mavs' trade move amid Lakers-Pelicans stalemate
With the trade deadline coming up at 3 P.M. today, stay tuned for any updates regarding big deals . On Barnes' trade to the Kings, Mavericks head coach Rick Carlise addressed the deal post-game.
The British Horseracing Authority (BHA) announced that all four of the scheduled race meetings in Britain on Thursday have been cancelled as it tries to contain the "outbreak". In a similar way to the human version of flu - a high temperature, lots of nasal discharge, a harsh cough and lack of appetite.
Horse racing in Britain will not resume until next Wednesday at the earliest after three vaccinated horses tested positive for the disease.
Separately, as a precaution, all of the trainers who had runners at the fixtures at Wolverhampton, Ludlow and Ayr this week have been informed that their yards have been placed under a temporary hold which means that they will not be able to make any declarations until their horses have been tested and cleared.
"We are scrupulous about observing the health status of horses in our care and taking the necessary steps to treat any condition that may affect them".
Eden Hazard to tell Chelsea FC about Real Madrid decision
A £60m move to the French giants on transfer deadline day last month did not go through. He has given many hints that he will be moving at the end of the season.
Consequently horses stabled north of the Murray River couldn't compete in the 2007 Melbourne Spring Carnival, which largely proceeded as per normal but with increased bio-security measures.
Racing will continue in Ireland at Dundalk on Friday, Naas on Saturday and Punchestown on Sunday, but no English horses will be allowed to run in Ireland.
A BHA release said the cross-over of horses at the tracks could cause infection to horses around Britain and in Ireland.
"The horses we ran at Ayr yesterday never came back to our yard and instead went to a non-racing isolation yard that is about 25 minutes away from where we are based".
Kristoff St. John's last soap episode airs Wednesday
John may have passed away earlier this week, but his final scene in the hit CBS soap didn't air until Wednesday afternoon. While his cause of death is still under investigation by the medical examiner, many have speculated that St.
"We have three confirmed cases and this morning have taken blood and swabs from all the others for testing".