ST. PAUL -- A contagious virus is affecting horses across the state.

Seven horses have shown symptoms of the equine herpesvirus-1 virus. Three had to be euthanized.

Minnesota Board of Animal Health spokesman Dr. Paul Anderson says the virus is typical this time of year but its affecting the animals differently from previous years.

Cases of the virus have been found north of the Twin Cities.

Anderson says the virus spreads through the air and affect horses that are close together.

He says there isn't a known cure for the virus. The best thing to do is make sure the animal is comfortable.

Anderson says there has not been confirmation of another case in the last few days. He says to talk with your veterinarian before taking your horse to events where other horses are present.