DENVER (AP) -- Colorado agriculture officials have confirmed that a horse that was used during the National Western Stock Show in Denver has a potentially fatal virus.

The 6-year-old gelding from Texas was part of a team of quarter horses that pulled a stagecoach during rodeo performances during the National Western Stock Show that ended Sunday.

The infected horse is among seven horses that have been quarantined at the National Western Stock Show coliseum due to concerns about equine herpesvirus, and a hold order was placed on six other horses still being tested.

Agriculture officials said Tuesday that horse owners who traveled to the stock show and participated in events in the coliseum should contact their veterinarian immediately if their horses become ill or have a fever.

The virus isn't transmissible to people.

Copyright 2013 The AP.