Several similar but apparently distinct conditions may exist, caused by various species or subspecies of "Borrelia" in North America. A regionally restricted condition that may be related to "Borrelia" infection is southern tick-associated rash illness (STARI), also known as Masters disease. "Amblyomma americanum", known commonly as the lone-star tick, is recognized as the primary vector for STARI. In some parts of the geographical distribution of STARI, Lyme disease is quite rare (e.g., Arkansas), so people in these regions experiencing Lyme-like symptoms—especially if they follow a bite from a lone-star tick—should consider STARI as a possibility. It is generally a milder condition than Lyme and typically responds well to antibiotic treatment.