The American dog tick is one of the ticks that harbors the organism that causes Rocky Mountain spotted fever, the most common tick-borne disease in the United States. The illness was first spotted in Montana and Idaho, although it is now prevalent in the southeast. Symptoms include sudden high fevers, severe headaches, fatigue, muscle aches, nausea, and sometimes rashes. Usually symptoms become apparent 3 to 12 days after the victim has been bitten. As the organisms spread through circulation they cause bleeding of microscopic vessels that consequently can cause the vascular system to collapse, leading to death. If diagnosed early, antibiotics can cure the illness.