What is the minimum feeding time required by a deer tick before it can transmit Lyme disease to a horse, and what is the estimated risk of infection from a tick bite in areas where Lyme disease is common?

 A deer tick must feed for more than 36 hours before it can transmit the Lyme disease spirochete. Even in areas where Lyme disease is common, the risk of acquiring Lyme disease from a tick bite is only between 1 to 3 percent, provided the tick has not fed for more than 72 hours.