Amblyomma americanum, also known as the lone star tick, is found in much of the 
eastern United States. Since the mid-20th century, the lone star tick has been 
implicated in human disease. Today, A americanum remains an important vector for 
tick-borne illness. In addition to others, species of Rickettsia, Ehrlichia, and 
Borrelia are all transmitted by the lone star tick. Recently described 
conditions such as Southern tick-associated rash illness and anaphylaxis to red 
meat following tick bites have been attributed to the lone star tick. Impressive 
local reactions also can result after bites from A americanum. Early treatment 
of tick-borne illness is crucial to ensure good patient outcomes. Tick-control 
measures also are an important part of disease management in endemic areas. We 
discuss the tick's biology, human illnesses associated with A americanum, and 
methods to control tick numbers and eliminate disease in local reservoirs.